Held to just 27 points in the first 30 minutes of play, including that two-point struggle in the second quarter, the Lions roared back by clobbering the Knights in the fourth behind their own suffocating defense.
That included a 20-0 run in a six-minute stretch of the final period as San Beda moved a win away from duplicating its 13-game streak when it won its last NCAA title 28 years ago.
Although assured of the top seeding in the Final Four and the twice-to-beat advantage, the Lions still fought back from a 27-35 deficit at the onset of the fourth in a game they could afford to lose with the contest marred by a debris-throwing incident.
"We know this game has no bearing for us," said San Beda coach Koy Banal. "But we have an obligation to go for the win each game."
The Knights, who led almost all throughout, fell to their fourth loss against 10 wins and into a tie with Philippine Christian U at second. The Dolphins walloped the Mapua Cardinals, 75-65, in the first game.
Jason Castro dished out an all around effort with 20 points, nine boards, six assists and six steals while 2004 rookie MVP Gabby Espinas chipped in 18 points for the Dolphins.
Letran and PCU, last seasons finals protagonists, will thus play each other in a knockout duel for the No. 2 seeding tomorrow, also at the Big Dome in what could be a virtual best-of-three since the two will face each other in the next phase.
San Beda will take on Mapua in the other Final Four contest.
The San Beda-Letran game was marred a debris-pelting incident sparked by the ejection of Letran mentor Louie Alas with 3.08 minutes to go in the contest.
Alas was contesting a flagrant foul called on Rafael Jazul on a driving John Escobal, insisting that it should have been ruled as an ordinary foul.