SAN DIEGO—After the Aztecs blew a 17-point first-half lead, Chase Tapley hit a 3-pointer with 2.8 seconds left to give San Diego State a 63-62 victory against Boise State on Wednesday night.

San Diego State (17-5, 5-3 Mountain West) needed Tapley's big shot after being outplayed down the stretch by the Broncos.

Mikey Thompson's 3-pointer with 3:16 left gave Boise State a 61-58 lead. Neither team scored until the Aztecs' Jamaal Franklin made a lay-up with 13.5 seconds left. Boise State's Derrick Marks made the first of two free throws but missed the second and Tapley rebounded to set up the winning shot.

Thompson got a chance at the buzzer to give his team a win but just missed. He and Marks finished with 16 points apiece for Boise State (15-7, 3-5).

James Rahon scored 16 points for San Diego State while Franklin had 14. Tapley finished his night with 12 and J.J. O'Brien had 10.

The Aztecs dropped out of the AP Top 25 for the second time this season Monday after losing 70-67 at Air Force on Saturday.

San Diego State had a 17-point lead in the first half and was up 10 at halftime before Marks scored seven straight points early in the second half to key Boise State's comeback.

The Broncos took their first lead of the game, 56-54, on Marks' 3-pointer with 5:41 left.

DeShawn Stephens tied it with an inside shot before Ryan Watkins hit a bank shot to give the lead back to the Broncos. Franklin made a reverse lay-up before Thompson quieted Viejas Arena with a 3-pointer for a 61-58 Boise State lead.

The Broncos played San Diego State close in two of their three games last year. At San Diego, the Aztecs rallied from 12 points down and then watched as a 3-pointer by wide-open Thomas Bropleh rimmed out at the buzzer of the Aztecs' 58-56 win.

In the Mountain West Conference tournament opener, Jamaal Franklin made an off-balance 3-pointer over a double-team at the buzzer to give top-seeded Aztecs a 65-62 victory.

With the Aztecs leading 47-41, Marks was whistled for a flagrant foul for dragging down Franklin from behind on a lay-up attempt. Franklin missed both free throws and Thompson hit a 3-pointer as Boise State closed to 47-44.

San Diego State took a 34-17 lead after DeShawn Stephens converted a three-point play with 5:57 to go before halftime. O'Brien's strong inside play and two 3-pointers by Rahon helped the Aztecs take control.

Boise State then outscored the Aztecs 11-4 the rest of the half to close to 38-28 at halftime. Thompson scored five points, including a 3-pointer, and Kenny Buckner made two buckets for the Broncos.

The Aztecs were once again without point guard Xavier Thames, who's been slowed by a back injury.