BYU (18-7, 8-3) is still in third place in the West Coast Conference, but the loss to a mid-level WCC team pretty much means it is out of the title hunt. San Diego improved to 6-4 and 13-12 and got the upset it wanted after nearly toppling No. 6 Gonzaga here six days ago.
The Cougars trailed the entire second half after taking an early 18-10 lead. They rallied midway through the half to cut an 11-point deficit to three, 56-53, with 9:10 remaining.
However, the Toreros scored six straight points out of a well-taken timeout by coach Bill Grier to regain the momentum and get its small but vocal crowd back into it.
The Cougars had another surge in them, however, and closed the gap to two with 4:09 left with a 9-0 run fueled by Tyler Haws. But Johnny Dee, playing on a gimpy ankle, drained a long 3-pointer 25 seconds after Haws' three-point play, and the Toreros held on to win.
BYU pulled within three points with 12 seconds left, but Dee made one of two free throws and the Cougars turned it over with seven seconds left when Haws and Matt Carlino got tangled up.
The Cougars started the game as if they were going to have another easy time with the Toreros, jumping to an 18-10 lead after eight minutes when Carlino made a steal and threw a nifty pass to Haws for a fast-break dunk.
But the Toreros put together a 10-2 run the next four minutes, capitalizing on several Cougar turnovers, and it went back and forth from there until San Diego pulled away at the end of the half.
Haws led BYU with 13 points at the break, and Carlino had nine.
Bronson Kaufusi's free throw with 4:42 left gave BYU a 29-28 lead as the Cougars tried to hold off the Toreros and fight off foul trouble. Davies picked up his second foul with seven minutes left in the first half and spent most of the rest of the half on the bench.
The Cougars had eight turnovers in the first half, and were out-rebounded 20-14.
Led by Haws' 6-for-7 effort, BYU shot 51.7 percent in the first half (15 of 29), but was just 3 for 10 from 3-point range.