The University Athletic Association of the Philippines (UAAP) high school baseball tournament returned in Season 88 after a six-year hiatus with defending champion University of Santo Tomas (UST) making sure to send a strong message to the rest of the field.

The Junior Golden Sox needed just seven innings to dispatch De La Salle Zobel (DLSZ) Junior Green Batters, 18-6, setting their title defense in motion on Wednesday at the Rizal Memorial Baseball Stadium.

But UST was not the only team making waves, as guest team PAREF Southridge made a grand entrance with a thrilling 13-12 walk-off win over Ateneo de Manila University.

The Admirals surged to a 10-2 lead by the fourth inning, building on three runs in the opening frame, a five-run second inning, and a run in each of the next two stanzas. Yet the Blue Eagles refused to back down.

Southridge ace Joaquin Salvador was tested in the top of the fifth, facing 14 batters as Ateneo rallied to score 10 runs and take a 12-10 lead.

However, Southridge showed it had arrived in the UAAP not just to compete, but to win, refusing to fold in the face of adversity.

Down 11-12 with two outs in the bottom of the ninth, the Admirals demonstrated their resilience. With JC Basañes at second, Blue Eagles head coach Pepe Jose intentionally walked Salvador to set up a force play.

Hitless all game, Matt Genota stepped to the plate and lined a grounder to Ateneo first baseman Tommy Oblea — but Oblea fumbled it, allowing Basañes to score and tie the game at 12.

Then came Luis Chavez, who wasted no time. On the first pitch he saw, Chavez singled to right field, bringing Salvador home for the walk-off victory.

Chavez led Southridge’s offense with three hits, three RBIs, and two stolen bases, while Francisco Abelarde and Basañes each contributed two hits.

Lorenzo de Guzman, Nicolas Sevilla and Oblea paced Ateneo with two RBIs apiece, while Rafael Blaza shone in six innings of relief only to falter with one out remaining. Blaza allowed just five hits and two earned runs while also adding three hits offensively.

Meanwhile, UST relied on two massive innings to secure its mercy-rule victory, scoring seven runs in the fourth and 10 in the sixth.

The Junior Golden Sox had built an 8-1 lead after the seven-run fourth, but the Junior Green Batters managed to score two runs in the bottom half on hits by Jeff Palanog and Juancho Gatmaitan, making it 8-3.

UST delivered the knockout in the top of the sixth, sending 14 batters to the plate against DLSZ pitchers Laurence Valeros, Jan Soriano, and Amadeus Trozado, with 10 crossing home to make it 18-3.

UST lefty Marcus Tolentino closed out the game, striking out the final three batters in the bottom of the seventh.

Shortstop Joshua Paragas, outfielder Joseph Paragas, third baseman Van Ibabao, right fielder Marco Kimilat, and first baseman Nash Ortiz each recorded two hits, with Ibabao also swiping two bases.

UST starter Eugene Hermozura threw 3 2/3 innings, allowing four hits and two earned runs while fanning five batters.

For DLSZ, starter Valeros gave up 10 hits and nine earned runs in 5 1/3 innings but contributed offensively with two hits, two stolen bases, and an RBI.