Defense spelled the difference in Game 1 of the University Athletic Association of the Philippines Season 85 men's basketball tournament best-of-three finals series.

In a chess match between two of the league's top tacticians, it was defending champion University of the Philippines head coach Goldwin Monteverde who drew the winning strategy that put his squad on the cusp of making a repeat.

The Fighting Maroons threw the Blue Eagles out of their rhythm with swarming defense, especially in the closing minutes of the fourth quarter, leading to a 72-66 victory in the series opener late Sunday at the Mall of Asia Arena.

Timely stops saved UP from a dry spell of more than three minutes as Ateneo was making a desperate run to comeback from a 10-point deficit.

"Going towards the game, we prepared for Ateneo. We know what kind of team Ateneo is. We really can't relax. We always talked about it, that playing against Ateneo, we should play really good defense," Monteverde said.

The Fighting Maroons kept pressuring the ball handlers of the Blue Eagles. They effectively clogged the driving lanes and even limited Ateneo's points in the paint to just 24.

Ateneo big man Ange Kouame had 15 points but shot 5-of-12 from the field, Dave Ildefonso even had a harder time with 3-of-12 shooting clip while forward Kai Ballungay was a non-factor on offense as he missed all his three shots.

"Actually, we also had some lapses but the good thing, even before, the team does not stop and they would always communicate to address those lapses. We were able to sustain it until the end of the game," Monteverde said.

Blue Eagles mentor Tab Baldwin acknowledged that the Fighting Maroons did a great job disrupting if not stopping their offensive flow.

"Execution during the whole game was difficult because the pressure from UP was really good," he said.