Thomas Velasquez helped the Twin Cities 12s Little League team keep its unbeaten run through District 3 All Stars play intact in the most dramatic way possible on Wednesday.

Velasquez hit a walk-off grand slam in the bottom of the sixth to lift Twin Cities to a 5-4 quarterfinal victory against Tiburon Peninsula.

Twin Cities (7-0) advances to the semifinals at 10 a.m. Saturday at Joe Wagner against Ross Valley (4-3). Twin Cities won the first meeting between the two teams, 8-4, on Monday. Ross Valley defeated San Francisco National 2-0 in a Wednesday quarterfinal.

Twin Cities has posted a 21-0 record in All Stars play across the 12s, 11s, and 9-10s divisions so far this postseason.

Velasquez had two of Twin Cities’ four hits for the game and also worked four innings as the starting pitcher. Grayson Hall and Mason Whitehead both had singles in the sixth inning and Chase Coghlan reached on an error to load the bases for Velasquez.

Tiburon Peninsula (3-4) gave Twin Cities all it could handle. Ryan Dupuis had two hits, three RBIs, and scored twice. John Stewart, Jr., also drove in a run. Dupuis pitched the first five innings, allowing one hit, one run, and striking out nine.

Mill Valley (7-1) also moved on following a 12-0 victory in four innings against Novato North (3-4). Oscar Karlen didn’t allow a hit in four innings of work, striking out four. Davis Marshall had two hits and drove in four runs. Karlen also had three hits and two RBIs. Beckett Glynn had two hits and two RBIs.

Mill Valley faces San Francisco American (5-2) at 1:30 p.m. Saturday at Joe Wagner. San Francisco American defeated West Marin 3-0 in the quarterfinals. Mill Valley edged San Francisco American, 4-3, on the first day of play.

Semifinals for the 12s, 11s, and 9-10s are all set to be held on Saturday with all three finals to be played Sunday at Joe Wagner.

The 11s semifinals sees Twin Cities battle Novato South at 10 a.m. followed by Mill Valley against Novato North at 1:30 p.m. — both at Boyle Park.

The 9-10s semifinals will be Twin Cities vs. Novato South at 10 a.m., then Mill Valley against Novato North at 1:30 p.m. — both at Strawberry.

Baseball

Chris Blyskal had three hits — including his second homer of the season — and drove in four runs to lift the San Rafael Pacifics to an 8-3 home win against Martinez on Thursday.

San Rafael (24-12 Pecos League) scored seven of its eight innings in the middle innings to pull away. Beau Dorman had two hits — including his fifth homer — and drove in two runs. John Bicos and Blake Diggle also had two hits each against Martinez (13-22).

Starting pitcher Alex Valasek worked seven innings, allowing six hits and two earned runs while striking out 10 to earn the win.

San Rafael was coming off a 7-6 road loss against Dublin on Wednesday. Braxton King had three hits and Diggle hit a home run but the Leprechauns walked off with the win in the bottom of the 10th inning.