Ohio State 85, Tennessee 84

SAN ANTONIO, March 22 — With yet another improbable, scintillating and heart-stopping comeback, the Ohio State Buckeyes are evolving into the Comeback Kids of this N.C.A.A. tournament

The Buckeyes followed up their stunning overtime win against No. 9 Xavier in the second round of the tournament with perhaps an even more impressive effort.

The top-seeded Buckeyes overcame a 20-point first-half deficit, Tennessee’s suffocating defense and Greg Oden’s foul trouble to outlast the fifth-seeded Volunteers, 85-84, Thursday night.

After looking confused by Tennessee’s pressure defense and fast-paced offense in the first half, Ohio State streaked back into the game in the second half.

The Buckeyes did most of this without Oden, who scored only 9 points and sank just two field goals.

Tennessee guard Ramar Smith’s layup attempt at the buzzer to win the game was swatted out of bounds by Oden. It was unclear whether the buzzer had sounded before the shot.

But most of this Buckeye comeback came with Oden on the bench, which was fitting because Ohio State won against Xavier in overtime after Oden had fouled out in regulation. The Buckeyes went small to match up with the Vols in the second half, slowed the game and got another big effort from the star of the Xavier game — the senior Ron Lewis.

But the game’s biggest point came from the freshman point guard Mike Conley Jr., who drove the lane for a wild left-handed layup with 6.5 seconds remaining. Conley’s shot flipped harmlessly off the rim, but a questionable foul call put him on the free-throw line with the score tied, 84-84.

Conley swished the first one but missed the second, setting up Smith’s attempt at a game-winner.

Tennessee lost despite hitting 16 of 31 3-point shots. The Vols also out rebounded the Buckeyes.

Lewis followed up his game-tying 3-pointer in the waning seconds against Xavier with another epic game. Lewis led the Buckeyes with 25 points, 18 in the second half. Lewis finished the game shooting 9 of 17 from the field.

Lewis and Tennessee’s Chris Lofton traded 3-point shots in the final two minutes, as Lewis gave the Buckeyes an 82-79 lead and Lofton answered back to tie the score.

That is when Oden made his biggest contribution of the game, hitting two free throws with 1 minute 38 seconds remaining to give Ohio State an 84-82 lead

With Ohio State Coach Thad Matta protecting Oden from getting his fifth foul, the Tennessee freshman Wayne Chism drew a call inside and made one of two from the free-throw line to pull the Vols within 84-83. With 38.7 seconds remaining, Smith made one of two from the line to tie the score, 84-84.

With a three-second differential between the game clock and shot clock, Conley took the ball to the rim himself to set up his game-winning free throws.

Ohio State looked destined to become the first No. 1 seed ousted from this tournament, as they trailed by 17 at the half. But instead, they are one game from reaching the Final Four. The Buckeyes will play Memphis on Sunday for a shot at the university’s first Final Four since 1999.

Ohio State entered the Round of 16 with a 19-game win streak, an elite center and a glut of skeptics who saw the Buckeyes as vulnerable to an upset.

But Tennessee Coach Pearl was skeptical of the Vols’ chances. Tennessee has lost to Ohio State by 2 points in Columbus during the regular season. Hefelt Tennessee’s pressure is easier to adjust to the second times teams see it.

Pearl’s theory did not hold much water after tip-off. The Vols blitzed out to first-half leads as big as 20 points, shooting 9 for 15 from 3-point range and 55.9 percent from the field thanks to either shooting wide-open 3-pointer or easy layups.

The Vols played virtuoso controlled chaos in the first half, turning the ball over three times and holding Oden to 2 points on one shot, a dunk.

The most intoxicating part of Oden’s potential, which he has flashed consistently this season, has been his defense. In a season in which he has struggled to get the ball and averaged fewer than 10 shots a game, Oden’s wingspan and shot-blocking instincts have been the most impressive part of his game.

But against Tennessee’s run-and-gun style, which is predicated on fast breaks, pressure defense and 3-point shooting, Oden’s menacing defensive presence was neutralized.

That is what Tennessee did early on. The Vols loosened the defense early with 3-point shooting and then attacked the rim once Oden got into foul trouble. With just under 11 minutes remaining, Oden got whistled for his second foul as he hooked a Tennessee player while trying to split a double team.

Ohio State trailed by 6 points at the time, and that is when Tennessee’s athleticism and ability to score took over.

Oden returned to the game with just over six minutes left in the half and Ohio State trailing by 16. Pearl schemed to take the ball at him, and on the Vols’ second offensive possession with Oden back in the game, he picked up his third foul.