PHOENIX -- As his Arizona Diamondbacks hammered the Milwaukee Brewers 8-1 Saturday night, manager Bob Melvin allowed himself to peek at the out-of-town scoreboard.

He liked what he saw. NL West leader San Diego lost. So did Los Angeles, San Francisco and Colorado.

"Not that I was looking at the scoreboard, which I usually don't. I didn't notice that our division lost all across the board," Melvin said sarcastically.

That left the surging Diamondbacks in fourth place, three games behind the Padres. After staggering to an 8-20 record in June, Arizona has won five straight and is poised to sweep a series for the third consecutive weekend. Four games separate the five teams in the NL West.

Saturday night's victory over the Brewers, who have lost five straight, was almost too easy. With Brandon Webb (10-3) outdueling Chris Capuano (10-5) in a showdown of All-Star pitchers, Arizona first baseman Conor Jackson homered twice as the Diamondbacks reached .500 (45-45) for the first time since June 21.

"We know what we're capable of," Jackson said. "We knew that June was a fluke for us. We started off (the season) hot, and I think we're getting right back on track."

The game was billed as a faceoff of All-Stars who came up together through the Diamondbacks' farm system. Arizona dealt Capuano to Milwaukee in 2003 as part of a multiplayer deal for Richie Sexson, who played 23 games for the Diamondbacks.

Webb and Capuano rank among the NL leaders in wins, winning percentage, ERA, innings pitched and shutouts.

But the hyped matchup didn't live up to its billing as the Diamondbacks jumped on Capuano, who hadn't lost in seven starts. Only Webb looked like an All-Star on this night, trimming his league-leading ERA to 2.52 by shutting out the Brewers on six hits in seven innings. Webb, who was lifted after 110 pitches, walked two and tied a season high with 10 strikeouts.

"My arm felt great," said Webb, who added that he relied more on breaking balls than his trademark sinker. "To get runs early, especially off Cappy, who's having a great year, it definitely makes a starter's job easier."

Since giving up a season-high seven runs to Seattle on June 27, Webb has yielded two runs in his last three starts, a span of 23 innings. And that doesn't count Webb's inning in the All-Star Game, when he retired Derek Jeter, David Ortiz and Alex Rodriguez.

Capuano (10-5) lasted only 3 2/3 innings, his shortest outing of the season. He allowed eight runs -- five earned -- and 10 hits.

"I never really could get in a rhythm out there," Capuano said. "I had real trouble locating the ball."

Capuano was in trouble from the first batter, surrendering a leadoff double down the left field line to Eric Byrnes, who scored on Luis Gonzalez double down the right field line one out later.

In the second, Capuano gave up three runs but all were unearned. Third baseman Jeff Cirillo's throwing error allowed one run to score and set the stage for two-out RBI singles by Damion Easley and Gonzalez, putting the Brewers in a 4-0 hole.

In the third, Capuano gave up a leadoff home run to Jackson into the bullpen down the left field line. One inning later, Jackson homered again, this time into the left field seats with a man aboard to make it 7-0. It was Jackson's second career multihomer game.

Johnny Estrada followed with his eighth home run to chase Capuano.

"To their credit, they were swinging the bats well and hit a lot of my mistakes," Capuano said.

The loss dropped Milwaukee eight games behind St. Louis in the NL Central, but manager Ned Yost said his team could only worry about salvaging the final game of this series.

"You can't bury your head in the sand," he said. "You get after it again tomorrow."

Notes

• It was Arizona's first game without shortstop and leadoff man Craig Counsell, expected to miss three-to-six weeks with a broken rib. Byrnes replaced Counsell at the top of the order and started the first and fourth innings with doubles.
• Stephen Drew, the Diamondbacks' first-round pick in the 2004 draft, made his major league debut at shortstop, going 0-for-3 with a walk and a run scored.
• Jackson struck out looking in the first inning, the third straight at-bat he was called out on strikes. He homered in his next two at-bats.
• Webb made his 116th start. He's third on Arizona's career list, behind Randy Johnson (192) and Brian Anderson (129).
• Milwaukee OF Tony Gwynn Jr., the son of former San Diego star Tony Gwynn, made his major league debut. He grounded out as a pinch-hitter in the sixth inning.
• Gonzalez' two doubles gave him 522 for his career, tying Ed Delahanty for 33rd on baseball's career list.
• Arizona C Johnny Estrada doubled in the third inning to stretch his career-best hitting streak to 10 games.
• Arizona is 33-29 against the Brewers, including 17-15 at home.