EL DORADO — Manteca’s few mistakes proved costly in its 3-1 loss at No. 7 Union Mine in their Sac-Joaquin Section Division IV playoffs out-bracket game Monday.

Pacific-bound pitcher Beth Hammer blasted a two-run homer in the bottom of the first inning to spot the Sierra Valley Conference champion Diamondbacks (18-5), who later scored an insurance run after a throwing error in the third.

The 10th-seeded Buffaloes (14-10) plated their lone run in the top of the third after Haighley Kissee drove in Melanie Ramos with a single. Ramos led off the inning with a double, and Manteca had a chance to score again with a runner on third but did not pull the trigger following a passed ball.

“We played a good game, we just couldn’t get it done when we had the chance,” Manteca coach Corey Navarro said. 

Manteca outhit Union Mine 6-5 and struck out only four times against the hard-throwing Hammer. Kissee also pitched all six innings and struck out six and walked three.

“She threw good enough for us to win,” Navarro said. “On that two-run shot we called a drop ball inside and she floated it over the plate, and (Hammer) is good enough hitter to hit that out. Other than that, (Kissee) pitched a great game.”

Aryanna Martinez went 2 for 3 to lead the offense. She’s one of four starting seniors to have played her last game for Manteca.

“They were 15-0 in their league and we went up there and gave them a great game,” Navarro said. “I’m proud of the girls and the season they had.”