PHOENIX (AP) - Ten days ago, Mark Reynolds was an obscure Double-A infielder.

Now he's the Arizona Diamondbacks' biggest bopper.

The 23-year-old third baseman homered twice and went 5-for-5 with four RBIs to help the Diamondbacks beat Houston 13-3 Friday night, handing the Astros their sixth straight loss.

Reynolds is batting .459 (17-for-37) with eight extra-base hits and 11 RBIs in his first 10 big league games.

``It's unbelievable,'' Reynolds said. ``It's been a great ride so far.''

Reynolds was promoted after Chad Tracy, the Diamondbacks' regular third baseman, went on the disabled list with a rib cage injury. Brian Barden, third baseman at Triple-A Tucson, also was hurt, opening the door for Reynolds.

``All the chips fell in place, and I was able to get my shot,'' Reynolds said. ``I've always heard if you get your shot, you have to take advantage of it because it may only happen once.''

Reynolds made manager Bob Melvin look smart. Melvin batted Reynolds in the cleanup spot for the first time on Friday night.

``It wasn't much of a move,'' Melvin said. ``It was easy to do. He's just going about his business. I don't think he knows where he's hitting in the lineup to tell you the truth.''

For the record, Melvin said Reynolds will be back in the No. 4 hole for his 11th major league game.

Melvin said he had heard good scouting things about Reynolds, Arizona's 16th-round pick in the 2004 draft. But Melvin didn't want to dissect Reynolds' crazy start.

``I really don't like talking about it,'' Melvin said. ``Just let him go out there and do his thing. Let's pretend he's not there.''

That's wishful thinking. The Chase Field crowd of 23,298 demanded a curtain call after Reynolds homered for the second time in the eighth inning.

Reynolds was instrumental as the Diamondbacks tied a club record with eight runs and eight hits in the sixth inning. He tripled to lead off the inning and then added a two-run homer, driving Dave Borkowski's first pitch 447 feet into the left-field seats.

Needing a double for the cycle, Reynolds hit a line-drive homer to right field off Chad Qualls in the eighth.

``I mean, I was trying to hit a double,'' Reynolds said with a chuckle. ``I'll take a fence-scraper any day. I'm just glad I didn't strike out.''

Carlos Quentin had two doubles and three RBIs for Arizona, which has outscored Houston 22-4 in the first two games of the four-game series. The Diamondbacks matched their season high with 17 hits.

Edgar Gonzalez (2-2), who was demoted to Arizona's bullpen last month, allowed one run and four hits in five innings. He took Randy Johnson's turn in the rotation after the Big Unit was hampered by forearm tendinitis.

``It's important because they gave me a chance to start again, and I did my job,'' Gonzalez said.

Woody Williams (1-7) allowed four runs and five hits in five innings for Houston. He struck out three and walked two.

Williams cruised through the first three innings, allowing only a single to Reynolds, before the Diamondbacks scored four in the fourth. Quentin hit a three-run double as the Diamondbacks took a 4-1 lead.

``There's nothing I could do that's in my control when things go like that,'' Williams said. ``To their credit, they strung some hits together in that inning.''

Carlos Lee had two doubles for the Astros, who are 0-5 on a seven-game road trip to San Francisco and Arizona. At 21-27, the Astros are a season-worst six games below .500.

``It certainly was their night,'' Houston manager Phil Garner said. ``Everything we threw, they hit.''

Hunter Pence hit two RBI singles, and Morgan Ensberg had a pinch-hit homer in the ninth for the Astros.