Diego Figueroa's 11-point fourth quarter kept San Juan ahead as Bayamón closed within four in the final minute.
San Juan's lead looked comfortable at the start of the fourth quarter, but a 14-4 Bayamón run cut the gap to single digits with under three minutes remaining.
Figueroa answered with back-to-back three-pointers, pushing his fourth-quarter total to 11 points and sealing the Titanes' sixth straight win at Capital Coliseum.
Athlead's live win-probability model had San Juan's odds dip to 61% during Bayamón's run before climbing back to 94% after Figueroa's second three.