MANILA -- University of Santo Tomas averted another meltdown and clamped down on the University of the Philippines en route to a 12-6 victory on Wednesday at the UP Diliman Baseball Field.

The upset marked UST's first win in the UAAP Season 85 baseball tournament, with the Golden Sox raising their record to 1-5.

The Fighting Maroons dropped to a share of second with their 4-2 slate.

UST peppered UP starting pitcher Jumbo Dela Cruz with four hits to score six in the opening salvo, with Adrian Aguilar taking charge.

This was the first-ever full night game in UAAP Baseball.

"Sinabi ko sa kanila, naka-adjust na naman tayo sa field. 'Yung kalaban kilala na natin, alam natin 'yung diskarte natin. At huwag nilang intindihin 'yung officiating, kasi nababagot sila sa officiating. So, ngayon masaya sila," longtime UST coach Jeff Santiago said after the game that ended at 11:04 p.m.

The designated hitter carved a double to score second baseman Justine Rosales and centerfielder Steve Dominguez to extend the lead to 5-0 before reaching home for a 6-0 lead.

Rosales and Dominguez once again scored in the second inning, facing Kiel Agojo on the mound this time as the lead ballooned to 11 at the end of the third.

UP's own designated hitter, Kobe Torres, then took over pitching duties to stop the bleeding for the Maroons.

Despite the lead, Santiago still saw glimpses of their very first game where they lost to Adamson, 9-8, and told his wards to keep their head in the game, saying, "Huwag niyong isipin na lamang kayo. Lagi niyong isipin na naghahabol kayo."

Dominguez ended with four hits and three runs in five at-bats, while Rosales finished with two hits and three runs in five at-bats, including the insurance run in the sixth, to pace the Golden Sox on offense.

It is in defense, though, where UST finished off the shocker, anchored by relief pitcher John Mark Bersales, who limited UP to just three runs despite allowing 13 hits after taking over the mound from Ivan Llave in the fourth inning with one out.

This steady hold spoiled UP centerfielder Ian Mercado's second home run of the season in the first inning and the huge turn up from shortstop Nano Asuncion, who had three hits in five at-bats, and right fielder Darren Mayo, who finished with two hits in five at-bats.