Kyrie Irving, Celtics Come Back to Beat Russell Westbrook, Winless Thunder

The Oklahoma City Thunder still haven't found the win column this season.

Oklahoma City dropped 0-4 with a 101-95 loss to the Boston Celtics on Thursday at Chesapeake Energy Arena. Kyrie Irving tallied 15 points, five assists and five rebounds in the interconference point guard showdown with Russell Westbrook, who countered with 13 points, 15 rebounds and eight assists.

It wasn't just Irving, as Marcus Morris drilled a go-ahead three in the final 30 seconds and added 21 points and 10 boards in the win.

Marcus Money Morris

Celtics' Plan to Take East Crown Is on Hold Until They Solve Offense

The Celtics were supposed to be the Eastern Conference's version of the Golden State Warriors with the return of Irving and Gordon Hayward to a team that finished a win away from the NBA Finals.

That plan is temporarily on hold because of an inconsistent offense, even after a win and 3-2 start.

The Celtics were 0-of-11 from three-point range in the first half and looked nothing like a squad featuring Irving, Hayward, Al Horford, Jayson Tatum, Jaylen Brown, Marcus Smart, Terry Rozier and Morris. That is simply too much talent to be 29th in the league in offensive rating, which is exactly where Boston was prior to Thursday's game, per NBA.com.

The it's-still-early qualifier applies to all teams, but it is even more apt for the Celtics. Hayward is returning from a broken tibia and dislocated ankle and is yet to score more than 14 points in a game this season. He was largely a nonfactor against OKC with five points on 1-of-5 shooting from the field.

Irving is also coming back from knee surgery, and Tatum and Brown have to adjust to playing alongside the ball-dominant point guard again after they were go-to options in the postseason.

The offense finally appeared to click in the third quarter when Boston poured in 40 points and overcame a 16-point halftime deficit in 12 minutes. The potential was on display when Tatum posterized Paul George and when Al Horford extended his game beyond the arc with three straight triples, but the unit is too inconsistent as a whole in the early portion of the season.

The silver lining for Boston is the realization its defense will keep it in almost every game.

It was tied for the league lead in defensive rating coming into the contest, per NBA.com, and was second in the NBA last season. In head coach Brad Stevens' system, players are constantly swarming outside shooters and cutting off penetration with quality wing defenders—such as Smart—and crisp rotations.

This is an NBA-Finals-appearance-or-bust season for the Celtics after LeBron James departed for the West, and the defense is once again championship-caliber. The same cannot be said about an offense that is stuck in neutral as Irving and Hayward work their way back.

Thunder's Defense Lost Without Andre Roberson

Celtics Come Up Big in the Third Quarter

Much of the national attention on the Thunder centers on the one-two punch of Westbrook and Paul George, and rightfully so, but the absence of Andre Roberson is a primary reason they have come out of the gates so slowly.

The swingman is sidelined with a knee injury, and the team's shortcomings without him were on full display when Boston exploded for the 40 points in the third quarter. OKC appeared to go through the motions for extended stretches, especially when Westbrook went to the bench with foul trouble, and no defensive stopper filled the void to alter the course of the quarter.

The Roberson-less defense reared its ugly head again in crunch time when the Thunder lost track of Morris, who drilled an open three from the wing to give the Celtics the lead for good.

It mirrored the early-season defensive issues, as the Thunder allowed at least 108 points in each of their first three games.

They even lost against the Sacramento Kings when Westbrook went off with 32 points, 12 rebounds and eight rebounds because the defense gave up 131 points. Sacramento isn't exactly a championship contender, so the performance was concerning to say the least.

Roberson is the underrated defensive leader of the supporting cast and brings a physical toughness that has been missing on that end of the floor. The Thunder's defensive rating was a formidable 96.6 when he was on the court last season compared to 108.4 when he was off it, per NBA.com.

Oklahoma City was once again unable to survive his absence Thursday even facing a struggling offense, suggesting the defense is nowhere near ready to compete with the best teams in the Western Conference.

Roberson's eventual return can change that.

What's Next?

The Celtics are at the Detroit Pistons on Saturday, while the Thunder host the Phoenix Suns on Sunday.