Espinosa's first shot tied the count at 60-all. In the ensuing play, he intercepted an errant inbound pass by John Arne and then dashed for the game-clinching breakaway layup with five ticks left before the final buzzer.
John Arne, which fought without top gunner Vincent "Inting" Reyes and coach Boy Te, had the final possession, but couldn't make one good offensive play.
Tipasi All-Stars trailed by 19 points, 29-10, early in the second period, but rallied back tenaciously to trim the deficit down to a matchstick at halftime, 36-37.
A see-saw battle ensued from that point on, but the Tipasi All-Stars displayed sheer grit and guts in the closing minutes of the game to complete what is by far the biggest comeback in SWFC history.
Despite absorbing its first loss in two starts, John Arne is still capable of making it to the finals as it only needs to win against Unilink this Sunday to set up an expected grudge rematch with Tipasi All-Stars.
Earlier, the Summit Drinking water defeated the Flammazine, 81-75.
The scores
First game
Summit (81) - W. Estorba 28, Mendoza 17, Luces 10, Nadera 7, Doblas 6, Estorba 4, Abapo 3, F. Estorba 3, Malinao 2
Flammazine (75) - Mosqueda 18, Cabrera 14, Baclay 14, Lawas 7, Malazarte 6, Rio 5, Mavi 5, Mordeno 4, Bullo 2
Second Game
Tipasi All-Stars (62) - Cabiluna 11, Espinosa 9, Mansubre 9, Felicitas 7, Zafra 6, Anciado 6, Logroño 6, Torregosa 4, Jabines 2
CX Plus John Arne (60) - Sullano 10, Lim 10, Noel 7, Sasing 7, J. Seno 7, Ocampo 6, A. Mauro 6, J. Mauro 3, Te 2 (GGM)