NEW YORK — Keita Bates-Diop and Tony Carr each had 25 points, but Carr’s assist to Josh Reaves under the basket with 3.1 seconds left gave No. 7 seed Penn State a 69-68 upset against No. 2 seed Ohio State in a Big Ten tournament quarterfinal at Madison Square Garden.

Despite trailing by as many as eight points during the second half, the Buckeyes (24-8) tied the score four times but couldn’t take a lead until Kam Williams buried a three-pointer with 5:02 to play for a 60-57 lead.

Penn State tied it on two more occasions, but Ohio State took a 64-62 lead when C.J. Jackson drove from the left wing, drew an extra defender and fed Andre Wesson on the other block with a bounce pass that he finished with 3:59 left.

Bates-Diop made it a two-possession game with a mid-range jumper from the right wing with 2:38 to play and answered a Julian Moore dunk with a layup to restore the four-point lead at 68-64. Penn State then cut it to one after a pair of Reaves free throws with 47.4 seconds left, and Ohio State called timeout with 41.5 remaining and leading 68-67.

The Buckeyes got the ball to Bates-Diop at the top of the circle with about eight seconds left on the shot clock, but Shep Garner stripped it loose as the Nittany Lions (21-12) brought the double team. They pushed it upcourt, where Carr found Reaves under the basket for a slam dunk with 3.1 seconds left to give the Nittany Lions a 69-68 lead.

Ohio State pushed it upcourt after a pair of timeouts, but Jackson’s three-pointer from the right wing was well short.

The Buckeyes have lost all three meetings to the Nittany Lions this season, the fifth time in school history they’ve lost three games to the same team in one season.

A first half of runs led to a 33-32 halftime lead for Penn State, marking the third time this season the Nittany Lions led the Buckeyes at the break. Penn State used a 12-0 run to take a 12-4 lead, but Ohio State responded with an 11-0 run of its own that grew to 16-2 and pushed its lead to 20-15 when Andrew Dakich scored on a driving scoop from the left block at the 8:15 mark.

It was the eighth field goal for the Buckeyes to that point, one by each player to have seen playing time. They would push the lead to six and had a chance to take the lead into the break on the final possession, but Micah Potter’s three-pointer rimmed out, as did Bates-Diop’s jumper from the left corner at the buzzer. Ohio State did not make a field goal during the final 2:34 of the half.

The Nittany Lions held the lead in large part to their tenacity on the offensive glass. Penn State turned nine first-half offensive rebounds into 14 second-chance points despite being without leading rebounder Mike Watkins, who was announced Thursday as being out for the tournament because of a knee injury that also cost him the final game of the regular season.

Carr had 14 first-half points and Lamar Stevens, who drew fouls on three straight possessions by driving hard to the basket, had 12 for Penn State.

Adam Jardy is a reporter with The Columbus Dispatch.