The Red Lions leaned on the season-high production of Jacob Cortez, who tallied 15 points, four rebounds and two assists with veteran James Kwekuteye having 12 markers and four boards.
San Beda head coach Yuri Escueta said though JRU is out of the Final Four race, the Red Lions can't underestimate the Heavy Bombers' tough defense.
"When you thought they were out, they still played hard. Good thing, we were able to match their energy in the fourth quarter, play defense and get rebounds," said Escueta of the Red Lions, currently in third place with a 12-5 card.
"You can't be lazy against them. This win is big for us, going into the postseason.
Agem Miranda had 19 markers, five rebounds, three assists and three steals but it wasn't enough as the Heavy Bombers sank to its sixth-straight loss of the season.
Earlier, Letran College won over Mapua University, 74-58, to get at least a playoff for the top two spots.
The scores:
First game
LETRAN (74) — Sangalang 21, Yu 10, Reyson 9, Caralipio 8, Javillonar 8, Ariar 6, Monje 4, Olivario 3, Guarino 3, Paraiso 2, Santos 0.
MAPUA (58) — Hernandez 13, Bonifacio 8, Pido 8, Nocum 6, Cuenco 5, Lacap 5, Soriano 4, Garcia 3, Salenga 3, Agustin 3, Mercado 0.
QUARTERS: 22-18, 46-32, 60-53, 74-58.
Second game
SAN BEDA (70) — Cortez 15, Kwekuteye 12, Alfaro 11, Bahio 10, Andrada 7, Sanchez 6, Payosing 5, Cuntapay 2, Visser 2, Cometa 0, Jopia 0, Tagala 0.
JRU (61) — Miranda 19, Medina 12, Dionisio 8, Delos Santos 6, Dela Rosa 6, Tan 6, Guiab 4, Sy 2, De Jesus 0, Arenal 0, Gonzales 0, Mercado 0.
QUARTERS: 24-15, 40-36, 53-56, 70-61.