JC Intal came through with a season-high 24 points, highlighted by rim-rattling slams that sent the Ateneo fans into a frenzy, as the Eagles matched their first round sweep in 2004 on a team built around Larry Fonacier.
Chris Tiu and Doug Kramer fired 19 points apiece while Macky Escalona and sophomore Rabeth Al-Hussaini tossed in 15 and 12 points, respectively, to underscore the Eagles balanced offensive sock, which the Tigers failed to neutralize.
"We went into this thinking its going to be a track meet because we know UST is a quick team," said Ateneo coach Norman Black.
But the Eagles, after barely taking a 28-27 lead in the first period, quickly left the Tigers behind with a torrid scoring run in the second quarter.
Ateneo unloaded 35 points in that stretch while holding UST to just nine points as the Eagles sat on a 63-36 cushion at the turn and never looked back at resumption of the contest.
The respite actually failed to cool down the Eagles as they sustained their pace and put in another 27-point splurge to put the outcome beyond doubt at 90-47, with still a full quarter left in the game.
Jojo Duncil, back from a one-game suspension for head-butting National Us Dave Catamora, led the Tigers with 24 points but failed to get enough support from the rest as the Tigers took their fourth setback against two wins.
Duncil scored 13-point first quarter points to keep the Tigers in the game.
But when Intal teamed up with Kramer, Tiu and Escalona in that decisive second quarter run, Duncil failed to keep pace and got sidetracked along with the baffled Tigers.
Earlier, University of the East outgunned State U, 96-84, to move up to second place with a 4-2 (win-loss) slate.
Bonbon Custodio had 20 points to lead five teammates with double-digit scores.
UE held Miguel de Asis to a season-low six points as UP fell to a fourth loss against two wins.
The Maroons played without top rookie Martin Reyes, whose father passed away recently. UP team manager Bombet Silva was also ejected late in the second quarter for misconduct.