Brent Mayne drove in three runs, including a two-run triple in the fourth. Roberto Alomar also had a two-run triple, and Brandon Webb (1-0) worked six effective innings for the win.

Charles Johnson hit a grand slam off Andrew Good in the eighth, cutting it to 9-5. The Rockies also loaded the bases against Stephen Randolph in the ninth, but Matt Mantei came on and struck out Jeromy Burnitz and Vinny Castilla before retiring Luis Gonzalez on a grounder for his first save of the year.

It was Mantei's 71st save with Arizona, breaking Byung-Hyun Kim's franchise record.

Webb, whose 2.84 ERA last year as a rookie was fourth-best in the National League (news), gave up a run-scoring double to Todd Helton in the first. But the right-hander settled down and finished with seven strikeouts. He allowed five hits.

Webb also had a pair of run-scoring singles, the first RBIs of his career.

The Diamondbacks, who managed just three hits in a 6-2 loss to the Rockies in their opener the night before, found their power in the fourth against starter Jason Jennings, scoring seven times on seven hits before Jeff Fassero got the last out.

Jennings was tough through three innings. He retired six consecutive batters after walking the first two he faced in the second.

But Sexson led off the fourth with a 409-foot shot onto the pavement of the swimming-pool area in right-center.

Alex Cintron and Shea Hillenbrand followed with back-to-back singles — giving the Diamondbacks their first multihit inning in 13 — and both scored on Mayne's triple down the right-field line.

Webb then singled through a drawn-in infield for a 4-1 lead, Jennings walked Steve Finley, Alomar drove his triple into the gap in right-center and Cintron hit an RBI single.

Mayne had a run-scoring double and Webb drove in another run in the fifth.

Webb got out of a jam in the third, striking out Preston Wilson and getting Burnitz on a grounder with runners at second and third.

Notes:@ Jennings is 0-3 in four career starts in Phoenix, with an 11.09 ERA. ... The Bank One Ballpark roof was closed because of the threat of rain, marking the second indoor game in two nights. Early season games in Phoenix are usually played under the stars before the roof is closed during the summer for air conditioning. ... Helton, 4-for-4 in the opener, went eight plate appearances into the season before making an out — striking out against Webb in the fifth after five hits and two walks. ... It was Johnson's third career slam.