Nightmare Matchups for Potential No. 1 Seeds in the 2021 Men's NCAA Tournament

Both for competitive and historical reasons, the four No. 1 seeds in the NCAA men's basketball tournament are the hunted.

To start, the rankings tell us they are the best teams in the country. Easy enough. And since 1985—when the men's tournament expanded to 64 teams—a No. 1 seed has won 22 of the 35 national titles. Plus, 57 of the 140 Final Four qualifiers held a top billing. There's no doubt it's the preferred position in the field.

But it also means 83 top-seeded teams in the last 35 years haven't reached the Final Four.

Prior to the unveiling of the 2021 bracket, we've outlined some of the most challenging would-be obstacles for potential No. 1 seeds. While the choices are subjective, the emphasis is on difficult matchups in the earliest round possible.

Biggest strength: Ohio State can score, score, score. The offense is fourth in adjusted efficiency, per KenPom.com. E.J. Liddell has developed into a strong post player, while Duane Washington Jr. and Justin Ahrens are great perimeter threats. The Buckeyes also have the fourth-best percentage on two-point jumpers, per Hoop-Math.

Biggest weakness: Opponents can score, score, score. Ohio State forces turnovers at one of the lowest rates in the country, ranking 333rd out of 347 active teams. Plus, the Buckeyes are no better than average at preventing offensive rebounds. If the other offense gets hot, Ohio State better be shooting just as well.

Nightmare matchup: Connecticut has a streaky offense, but James Bouknight is an elite scorer if his perimeter shots are falling. Plus, since he returned from injury in February, the Huskies have held opponents to a 28.9 three-point clip and 39.2 mark overall.

Biggest strength: Led by National Player of the Year front-runner Luka Garza, Iowa has immense scoring potential. Garza is a force in the post, and the Hawkeyes have several great options on the outside. Garza, Joe Wieskamp, Jordan Bohannon and CJ Fredrick are the core of the 11th-best three-point shooting team.

Biggest weakness: Iowa ranks 316th in opponent turnover percentage, which can be especially problematic if its perimeter defense is struggling. While it has improved lately, that plagued the Hawkeyes badly early in the season.

Nightmare matchup: After a mediocre start, Virginia's perimeter defense has tightened. In the last 10 games, opponents have shot 33.3 percent from three-point range. On offense, the Cavaliers rank 18th nationally with a 38.1 clip. Combine that with the slowest tempo in the country, per KenPom, and UVA can stifle Iowa.

Biggest strength: Alabama's defense can be suffocating, especially on the perimeter. Opponents have connected on just 28.2 percent of their long-range attempts. Against SEC competition, that number even dropped to 25.9 percent.

Biggest weakness: On the opposite end, the Crimson Tide are awfully reliant on three-pointers. Their 35.5 percent clip is reasonably efficient, but 47.0 percent of Alabama's shots are from the perimeter. If threes aren't falling, the Tide may struggle to generate offense. They rank 255th in field-goal percentage at the rim and 347th—dead last—in two-point jumpers, according to Hoop-Math.

Nightmare matchup: Alabama has the nation's eighth-fastest tempo, per KenPom. Loyola-Chicago, however, is among the slowest-paced teams, has a 36.8 three-point clip and cedes the fourth-lowest rate of offensive rebounds. The Ramblers could slow the game and clip the Tide in a second-round clash.

Biggest strength: Led by All-American candidates Ayo Dosunmu and Kofi Cockburn, Illinois boasts a highly efficient offense. Illinois excels at getting to the rim and shooting a bunch of free throws. Although they're minimally dependent on the perimeter, the Illini rank 24th nationally with a 37.9 three-point percentage.

Biggest weakness: Perimeter defense, on the other hand, is questionable. The recent trends are promising, but the Illini are 8-5 when their opponent hits 35-plus percent from three.

Nightmare matchup: Oregon's overall stats are deceiving because Will Richardson missed half of the season. Since his return in early February, the Ducks are 11-3 and have buried 40.9 percent of their triples. Oregon could be a Sweet 16 matchup.

Biggest strength: Balance is the key for Michigan, which can dictate a game on either end of the floor. While the Wolverines are eighth nationally in three-point percentage, they rank fourth in two-point defense and 13th in opponent assist rate.

Biggest weakness: Michigan doesn't have any glaring issues when healthy, but Isaiah Livers' broken foot could change it. His absence will be especially felt on the perimeter, where he's a 43.1 percent shooting and one of the better defenders.

Nightmare matchup: Potentially waiting in the Sweet 16, Creighton shoots a ton of threes and is 43rd with a 37.1 percentage. Plus, while ranking 15th on two-point shots, the Bluejays are comfortable slowing it down. They have the 11th-best effective field-goal percentage in non-transition offense, per Hoop-Math.

Biggest strength: There isn't a stronger perimeter group in the country. Jared Butler and Davion Mitchell both average 14-plus points and four-plus assists while converting at least 42.9 percent from three-point range. MaCio Teague, Adam Flagler and Matthew Mayer are all 38.6 percent or better.

Biggest weakness: Baylor has minimized the impact of a thin frontcourt, but illness and foul trouble have limited Jonathan Tchamwa Tchatchoua lately. If he's struggling at all, Baylor's under-the-radar concern of giving up second chances may be crushing. The Bears allow the 53rd-highest rate of offensive rebounds.

Nightmare matchup: As a likely 2-3 seed, Houston probably won't be a factor for Baylor until the Elite Eight. However, the Cougars have the fourth-best perimeter defense and grab offensive rebounds at the second-highest rate.

Biggest strength: In not-so-breaking news, the object of basketball is to score points. Gonzaga is downright incredible on the offensive end, averaging 92.1 points per game with a 61.0 effective field-goal percentage that leads the country.

Biggest weakness: While the six-man rotation is outstanding, it's six players. Nobody else has provided a consistent impact in key games, so Gonzaga desperately needs to avoid foul trouble or get a little production from Aaron Cook, Julian Strawther, Dominick Harris or Oumar Ballo.

Nightmare matchup: This explains our level of respect for Gonzaga: Short of an injury, the other No. 1 seeds. In particular, Michigan and Illinois can give Drew Timme problems with Hunter Dickinson and Kofi Cockburn. Fast or slow, Gonzaga is an elite offense. But it's far preferable to slow the tempo, put pressure on Timme defensively and force the Zags to score in the half court.

Statistics courtesy of KenPom.com or Sports Reference unless otherwise noted. Follow Bleacher Report writer David Kenyon on Twitter @Kenyon19_BR.