Jeff Baker hit two three-run homers, Garrett Atkins also drove in six runs and Justin Hampson won in his first major league start as the Colorado Rockies beat the San Francisco Giants 20-8 on Monday night.

The Rockies, who had a season-high 19 hits, tied the club record for runs, reaching 20 for the third time, the last on Sept. 20, 2005, against San Diego.

Baker, a September call up, hit his first major league home run in his final at-bat at Arizona on Sunday, and then hit two more in his first two plate appearances Monday. The 25-year-old outfielder also had a double against the Giants.

Hampson (1-0) had made two relief appearances since being called up from Triple-A Colorado Springs on Sept. 7. He went five innings in his first start, giving up 10 hits and six runs.

The Giants entered Monday's game trailing San Diego by four games in the NL West and they were 3{ games behind Los Angeles in the wild-card race. San Diego and Los Angeles met Monday night.

Baker followed his three-run shot to right in the first inning with a towering 435-foot homer to left in the second that landed high up in the bleachers and bounced into the concession stands area.

Atkins had two doubles and two singles in his fifth career four-hit game.

Baker's first homer highlighted a six-run first inning against Giants starter Noah Lowry (7-10). The Rockies had four singles, a walk and a home run before the Giants recorded an out.

Lowry was pulled after 1 1-3 innings, the shortest outing of his career. He gave up nine hits and a career-high nine earned runs. Lowry has never pitched well at Coors Field and saw his ERA in Colorado climb from 8.06 to 12.05.

Hampson got off to a rocky start, giving up three runs and three hits in the first inning. Barry Bonds had an RBI single and Ray Durham added a two-run homer, his 24th.

Matt Holliday had three hits and three RBIs for the Rockies, who had 18 hits five times this season, the last at Los Angeles on Sept. 3.

Notes: If Rockies manager Clint Hurdle had a vote for NL rookie of the year, his choice would be simple: Giants RHP Matt Cain. Cain is 13-9 this season with a 3.75 ERA. ``He's gotten better as the year's gotten on,'' Hurdle said ... Rockies C Alvin Colina had an RBI single in his first major league at-bat. ... C Chris Iannetta walked three times and was the only Colorado starter not to score.

© The Canadian Press, 2007