The Blue Knights, who trailed mostly in the first half, started the third period on a 9-2 blast and led by as many as 13 points before taking the quarter, 63-56.
Xavier managed to keep at pace with the hosts in the final period and even trimmed the deficit at 81-78 with only 1:08 to go. But that proved to be the closest they can get as Ateneo retaliated with a 5-0 run to seal the game.
Nelson Te topscored with 14 points for the Blue Knights but got sidelined with an ankle injury midway in the third. Marvin Te and Alexis Maiz took over in Tes absence as they chipped in 13 apiece, while Datu Sinsuat finished with 11. Chris Abrio led Xavier with 15 markers.
Game two of the Ateneo-Xavier exhibitions is scheduled today at 10 A.M. Lorenzo Gahol.