B/R NBA Expert Predictions for Celtics vs. Bucks + Suns vs. Mavericks Game 7s

There's nothing better in the NBA than a Game 7.

Unless, of course, there are two Game 7s featuring some of the league's best players for the right to advance to the conference finals. That would be better.

A trip to the NBA's Final Four is on the line Sunday, when the Boston Celtics host the Milwaukee Bucks before the Phoenix Suns welcome the Dallas Mavericks to town in a win-or-go-home scenario for all clubs.

The full details:

Game 1:

• (3) Milwaukee Bucks at (2) Boston Celtics
• 3:30 p.m. ET on ABC
• Winner plays the Miami Heat in the Eastern Conference Finals.

Game 2:

• (4) Dallas Mavericks at (1) Phoenix Suns
• 8 p.m. ET on TNT
• Winner plays the Golden State Warriors in the Western Conference Finals.

Here's what to watch for in both Game 7s, including every team's keys to victory, X-factors, what to keep an eye on and an official prediction for which franchise ultimately moves on.

Keys to Victory: Go small, but keep Giannis Antetokounmpo on the floor

While the status of Robert Williams III's knee could affect Milwaukee's lineups, the Bucks have had more success this series when they've gone away from using a traditional center.

The Bucks have been outscored by 55 points in the 151 minutes Brook Lopez has played over the first six games, and the 34-year-old has yet to hit a single three-pointer (0-of-7). His lack of floor-spacing really hurts Antetokounmpo's ability to get one-on-one matchups in the paint.

Milwaukee's best lineup has been with Antetokounmpo and Bobby Portis in the frontcourt with Jrue Holiday, Pat Connaughton and Wesley Matthews on the wing (plus-31.7 net rating in 31 total minutes). Surrounding Antetokounmpo with shooters has long been a recipe for success, especially against this stifling Boston defense.

Antetokounmpo may also have to play all 48 minutes, as the Bucks are a whopping 30.2 points per 100 possessions better with the two-time MVP on the floor this postseason.

X-Factor: Pat Connaughton

While the Bucks have gone to Wesley Matthews when they needed defense or Grayson Allen when outside shooting was the priority, Connaughton offers a bit of both and has quietly been Milwaukee's third-leading scorer this series.

With no Khris Middleton (more on him below), the Bucks have been desperate for offense outside of Antetokounmpo and Jrue Holiday (who's only shooting 35.3 percent overall in the first six games).

The Bucks should consider starting Connaughton, who's averaged 12.4 points and 4.2 rebounds while connecting on 60 percent of his shots since Game 2. He's shown the ability to heat up at the right time (20 points fueled by six three-pointers in a series-winning Game 5 against the Chicago Bulls in Round 1) and could help prevent Boston from double-teaming Antetokounmpo for stretches.

Keep an Eye On: Khris Middleton's status

The Bucks' All-Star forward has yet to play in the series because of a left MCL sprain, and while he hasn't officially been ruled out for Game 7, it appears unlikely that Middleton will play.

It would be unfair to insert Middleton into a Game 7 and immediately ask him to line up next to Jayson Tatum or Jaylen Brown, especially if he's far from 100 percent. The 30-year-old averaged 14.3 points, 6.3 rebounds, 6.3 assists and one steal in three regular-season meetings against the Celtics and would be a huge boost (if healthy) to the Bucks now.

Keys to Victory: Get Jayson Tatum going early, don't let Giannis Antetokounmpo win the game

As we saw in Game 6, Game 7 should be a heavyweight fight between Tatum and Antetokounmpo.

The two combined for 90 points, with Tatum's 46 ultimately leading the way.

Unfortunately for Boston, Tatum hasn't given them a consistent scoring output and has fallen into the trap of taking some tough, contested shots instead of working for better looks. This series would already be over had he not gone 4-of-19 for 10 points in a two-point loss in Game 3, and Tatum has shot 41.4 percent or worse in four of his 10 playoffs contests thus far. The Celtics have to make sure to get him some good looks early to set the tone for the rest of the game.

With Khris Middleton unlikely to play and Jrue Holiday struggling with his shot this series, the defensive game plan is simple. Make life as difficult as possible for Antetokounmpo. The reigning Finals MVP has gone off the last three games with Robert Williams III sidelined, averaging 39.3 points, 16.3 rebounds, 4.7 assists and 1.0 blocks while shooting 49.4 percent overall.

No one else on the Bucks roster should scare the Celtics right now. All attention has to be paid to Antetokounmpo, even if it means more open looks for some of the team's role players.

X-Factor: Three-point shooting

While Boston wasn't a great three-point shooting team this season (35.6 percent, 14th overall), the ability to connect from deep could swing a Game 7.

The Celtics have shot a scorching 41.5 percent from three in their three wins this series, a figure that falls to just 32.5 percent in three losses.

Grant Williams, one of Boston's only reliable knockdown shooters at 41.1 percent this season, has gone just 1-of-8 from deep in his three starts this series while averaging 3.7 points in 27.8 minutes.

Keep an Eye on: Robert Williams III's status

Williams has missed the past three contests for Boston while dealing with a bone bruise after colliding with Antetokounmpo in Game 3.

Celtics head coach Ime Udoka said that Williams is day-to-day and that it's a matter of pain tolerance when deciding if the 24-year-old center can play.

A huge part of Boston's defense and arguably the team's best option when guarding Antetokounmpo, Williams' status could determine the outcome of Game 7.

Legacies are on the line for Game 7.

A win for the short-handed Bucks only helps cement Antetokounmpo as the greatest player in the game today and keeps Milwaukee's hopes of winning back-to-back titles alive.

A win for Boston would mean Tatum's team has now gone head-to-head with both Kevin Durant and Antetokoumpo in the first two rounds and slayed both, putting the 24-year-old in the conversation as a top-five player in the league, one who's already put together a terrific playoff resume.

Normally playing the game in Boston would be an advantage for the Celtics, but road teams are 4-2 in this series. The Bucks have already won twice in Beantown and should have no worries about playing in front of a hostile crowd.

So who wins?

Fortunately for Boston, they have a far better chance at getting Williams back than Milwaukee does Middleton.

If Williams' knee injury is truly a matter of managing pain, it's hard to imagine him missing the most important game of the season. In the three games that Williams has suited up, Antetokounmpo has shot just 43.9 percent overall, compared to 49.4 percent when the defensive whiz has sat.

No one can blame the Bucks for coming up short while missing their second-best player, which is ultimately what happens here.

Prediction: Celtics win 103-98

Key to Victory: Spread the floor with Maxi Kleber

Despite starting every playoff game for the Mavs this series, Dwight Powell has only received 12.3 minutes per contest.

This isn't by accident, as Dallas has used Kleber's three-point shooting ability to pull Deandre Ayton out of the paint and give Luka Doncic and Jalen Brunson more room to operate.

When Powell has been on the floor with the rest of the Mavs' starting five this postseason (Doncic, Brunson, Dorian Finney-Smith and Reggie Bullock), Dallas has a disastrous net rating of minus-11.9 in 52 minutes. With Kleber in place of Powell, the Mavericks are beating opponents by 14.6 points per 100 possessions, a huge 26.5-point swing.

Dallas should consider starting Kleber over Powell for the first time these playoffs, avoiding what's been a terrible lineup for them altogether.

X-Factor: Literally any player outside of Doncic playing well on the road.

Strangely enough, Doncic has played far better in losses this series than in wins.

The 23-year-old superstar is giving Dallas a heroic 36.0 points on 50.7 percent shooting in three losses compared to 28.3 points on 40.8 percent shooting in three victories. The Mavs have been a better team when Doncic can play more of a distributor role with everyone else hitting open shots.

Unfortunately, role players almost always play better at home in the postseason, which has once again proven true here. Since Dallas is essentially 90 percent solid role players, this is a problem with Game 7 taking place in Phoenix.

Brunson, Finney-Smith, Kleber, Bullock and Spencer Dinwiddie are averaging a combined 70.0 points a game in home games (all victories) for the Mavs, compared to just 48.0 on the road (all losses). Doncic is the only player who's proved he can excel no matter where the game is being held.

Be it Brunson, Dinwiddie, Finney-Smith or literally any other player outside of Doncic, someone has to step up and have a big game, something we've rarely seen this postseason.

Keep an Eye on: Mavs attacking Chris Paul

While Mikal Bridges has drawn the majority of the matchups against Doncic in the series, Dallas should do everything it can to switch Paul onto their 6'7" point guard.

Doncic is shooting 57.9 percent in the series when Paul is the primary defender per NBA tracking data, scoring 27 points and dishing out eight assists in just 10:09 of matchup time. He's got a quick enough first step to get by the 37-year-old and has the size to back him down, either getting a one-on-one matchup in the paint or forcing a help defender to come over and creating an open shooter for Dallas.

When Bridges, Devin Booker, Jae Crowder, Cam Johnson or Deandre Ayton are guarding Doncic this series, his field goal percentage falls to 43.6 percent.

Don't be surprised to see Dallas be more patient and work to get Paul on Doncic as much as possible in Game 7.

Key to Victory: Just keep the game close

It's no secret that the Suns have been quite good when the game gets close, and their regular-season success has carried over into these playoffs.

Phoenix was first in the NBA in clutch time net rating (plus-33.4 in 130 minutes), posting more than twice the rating as the second-place Milwaukee Bucks (plus-15.9 net in 122 minutes).

The Suns' clutch time net rating this postseason is nearly identical (plus-32.4 rating) to their regular-season mark, with Chris Paul and Co. dissecting teams on command with the game on the line.

No game in this series has been particularly close, however, so Dallas has gotten to avoid Phoenix's clutch time wrath. The Suns don't need to blow the Mavs out of the water during the first three quarters, but rather just keep the game close and do what they've done all season to dispose of their opponent during the last five minutes.

X-Factor: Jae Crowder's streaky shooting

Crowder is either the best shooter in NBA playoff history or the worst player to ever come in contact with a basketball. There can be no in-between.

His history has given us both sides, a tradition that's now carried over to this postseason.

After making just three total three-pointers against the New Orleans Pelicans (3-of-26, 11.5 percent) in a six-game series, Crowder is drilling 48.4 percent of his outside looks against the Mavs (15-of-31, 48.4 percent).

While the Suns can regularly go to Devin Booker, Deandre Ayton or Paul for offense, having Crowder knock down threes at a Steph Curry-like rate could swing a game—and in this case—a series.

Keep an Eye on: Chris Paul finally showing his age?

While age is just a number for players like Paul, Kyle Lowry, LeBron James and others in their mid-to-late 30s, Paul just hasn't looked the same as of late following his 37th birthday.

In his first eight games this postseason, the then 36-year-old averaged 22.6 points, 9.9 assists, 1.6 turnovers and shooting 58.0 percent overall. In his last four contests, these numbers have fallen to 9.3 points, 6.3 assists and 4.5 turnovers on 50.0 percent shooting from the field.

With so much talent on the roster, the Suns don't need Paul to have a big Game 7, but it's worth noting that Phoenix is just 1-3 since the future Hall of Famer celebrated his most recent birthday on May 6. The Suns can't rely on him to defy Father Time forever and should already be making the necessary adjustments to his workload.

While the away team has held a 4-2 advantage in the Boston Celtics-Milwaukee Bucks series, this just hasn't been the case here.

The home team has won all six games, a good sign for a Suns squad now back in Phoenix.

The Mavericks have the worst road net rating of any team still left in the playoffs (minus-9.6), while the Suns' home net rating (plus-13.8) is only surpassed by the two franchises who have already advanced (Miami Heat, Golden State Warriors).

We've received no evidence of Dallas' role players being able to consistently hit shots on the road, and even a monster night from Luka Doncic can be overcome if no one else is stepping up.

While it would be great for the fourth-seeded Mavs to advance, the Suns need this game to keep their title window open with Chris Paul 37 years old.

Dallas had a great season and has the best overall player on the floor, but the Suns are simply the better team, especially at home.

Prediction: Suns win 115-102