Clint Barmes had both Colorado RBIs as the Rockies out-dueled the San Francisco Giants 2-1 in 11 innings Tuesday at AT&T Park.

Barmes’ two-out double off Giants reliever Santiago Casilla scored Miguel Olivo and proved to be the difference in the pitcher-dominated game.

Casilla (1-1) allowed the one run on two hits and one walk in 2/3 of an inning. He was one of five Giants pitchers and 10 combined chuckers used in the game.

Rafael Betancourt (1-1) pitched one perfect inning to earn the win. Manuel Corpas closed the door to get his fifth save of the season.

Barmes got his first RBI in the seventh inning when he hit a sacrifice fly to again score Miguel Olivo and tie the game at 1-1. Andres Torres opened the scoring with a solo home run in the fourth.

Giants starter Barry Zito continued his bounce-back season, going seven innings while allowing one run on four hit and three walks. He struck out eight and lowered his ERA to 2.78 and is throwing like the pitcher San Francisco envisioned when they signed him to a seven-year, $126-million contract in 2006.

Colorado starter Jason Hammel was also up to the task. He gave up seven hits, walked none and also allowed a run to score in 6 2/3 innings.

The finale of this three-game set goes tomorrow at 10:15 pm ET.