The Cardinals face the Philippine Christian University Dolphins at 4 p.m. while the Altas battle the San Beda Red Lions at 2, both looking for their third victory in four games.
The three other teams with 2-1 (win-loss) records are reigning titlist San Sebastian, Letran and Jose Rizal.
Mapua is expected to lean anew on veteran Jeff Martin, who anchored the Cardinals two victories.
The Dolphins, who dropped a 72-75 overtime loss to the Stags last Wednesday for their second defeat against a win, must also watch out for Mapua skipper Christian Guevarra.
It was Guevarra who sank a pair of pressure-packed free throws with no time left that lifted the Cardinals to a 61-59 OT win over the Altas last Monday.
But more than the combined offensive efforts of Martin and Guevarra, the Cardinals are also expected to flaunt their vaunted defensive game.
Mapua held their opponents to an average of 58.5 points in its two wins.
The Altas, on the other hand, are aiming to get back on track after losing to the Cardinals with a win over the Red Lions, another team hoping to bounce back from a pair of sorry losses.