Manteca High opened the Valley Oak League season Wednesday with a tough 21-15 home loss to Oakdale.The defending league champion Buffaloes (0-1, 5-4) jumped out to a 6-0 advantage, adding three more in the third only to see the Mustangs come roaring back.“Ninety-nine out of 100 times, these are games you win when scoring 15 runs,” said Manteca coach Neil MacDannald.Oakdale (1-0, 5-3) used an eight-run fourth to leap-frog ahead.Down 12-9, the Buffaloes tied the game in the bottom half of the frame. Junior infielder Ronaldo Tijero, who went 3 for 4 at the plate, had the key hit in the inning with an RBI double. He scored on Greg Jones’ bases-loaded walk.Preston Brunk, who came in relief of starting pitcher Tanner Emes, settled his team down by limiting Manteca to three runs.Oakdale took advantage of an error in the fifth, with Tyler Hall delivering a two-run single up the middle.