Arizona’s Brandon Webb picked up his 20th win of the season, beating Cincinnati. Associated Press Photo.

The slumping Arizona Diamondbacks needed a terrific start from Brandon Webb, and the ace delivered against the Cincinnati Reds.

Unfortunately for Webb and the Diamondbacks, the Los Angeles Dodgers are rolling right now.

Webb tossed eight shutout innings to become the National League’s first 20-game winner, and Arizona beat Cincinnati 3-2 on Friday to end a six-game losing streak.

“Every win right now is a must-win for the whole team,” Webb said.

Webb (20-7) outpitched Aaron Harang to earn his first victory since Aug. 21. Arizona remained 31⁄2 games behind the NL West-leading Dodgers, who won 7-2 at Colorado.

James Loney drove in three runs and Chad Billingsley (15-10) pitched six solid innings for Los Angeles, which has won three straight and 11 of 12.

“If we keep winning, we’ll be all right,” Billingsley said. “We’re where we want to be, we want to keep playing well, and that’s the only thing we can control.”

Milwaukee at Philadelphia and Atlanta at the New York Mets were postponed by rain. The first two games of the Chicago Cubs’ weekend series at Houston were postponed Thursday with Hurricane Ike barreling toward the Texas coast.

Arizona’s shaky bullpen nearly blew Webb’s victory in the ninth. Closer Brandon Lyon gave up four base hits, including a two-run single by pinch-hitter Jeff Keppinger, before manager Bob Melvin summoned Chad Qualls.

“At that point, I had given (Lyon) enough rope, and I needed to go get him,” Melvin said.

Qualls entered with runners on first and third, and struck out pinch-hitter Jerry Hairston Jr. for his third save in 11 chances.

Lyon also blew a save in a wrenching loss at San Francisco on Wednesday, and Melvin hinted he may make a switch at closer.

“Tomorrow, we’ll deal with some of the issues that we need to take care of,” Melvin said.

Webb became Arizona’s first 20-game winner since 2002, when Randy Johnson won 24 games and Curt Schilling won 23.

Harang (4-16) gave up an unearned run and four hits in seven innings.

At Denver, Loney, Manny Ramirez, Matt Kemp, Andre Ethier and Angel Berroa had two hits apiece for Los Angeles.

“We’ve jelled,” Kemp said. “We’re getting the job done on the pitching side and hitting side. Everything’s just clicking for us right now.”

Jeff Francis (4-10) allowed three runs and six hits in six innings for Colorado.

Pirates 10, Cardinals 2

Nate McLouth homered and had a career-high five RBIs to lead the Pirates to the win.

Paul Maholm (9-8) pitched into the ninth inning for last-place Pittsburgh, which snapped a six-game losing streak and won for the fourth time in 21 games.

Rookie Luis Cruz also had three hits for the Pirates, who finished with 14 hits.

Pittsburgh improved to 8-7 against St. Louis, getting its most wins in a season against the Cardinals since 1997.

Marlins 2, Nationals 1

At Miami, Scott Olsen got his first win in 10 starts and Jorge Cantu hit a record-setting home run for Florida.

Olsen (7-10) gave up one run and six hits in six innings for his first win since July 19 against Philadelphia. Matt Lindstrom pitched a perfect ninth to get his third save in six opportunities.

Cantu hit his 25th homer in the fourth to tie it at 1, making the Marlins the first team in major league history to have four infielders hit at least 25.

Mike Jacobs (32), Dan Uggla (30), Hanley Ramirez (29) and Cantu have accounted for 116 of the Marlins’ 188 homers this season.

Giants 5, Padres 2

Jake Peavy had a rare poor start at home and San Francisco took advantage, getting a go-ahead home run from rookie Travis Ishikawa.

Peavy (9-11) allowed five runs and a season-high 11 hits in eight innings for the Padres. It was the first time in 14 home starts that Peavy has allowed more than three earned runs.

Ishikawa hit a solo drive in the sixth to give the Giants a 3-2 lead.

Jonathan Sanchez (9-10) allowed two runs and six hits in six-plus innings, ending a nine-start winless streak with his first victory since he beat Oakland on June 29.

AMERICAN LEAGUE

Red Sox 7, Blue Jays 0

Tim Wakefield pitched eight innings to bounce back from his shortest start in 15 years, helping the Boston Red Sox stop their AL East slide with a 7-0 victory over the Toronto Blue Jays Friday.

Kevin Cash hit a three-run homer, David Ortiz and Jed Lowrie each drove in a pair of runs and the Red Sox improved to two games out in the AL East behind Tampa Bay. Earlier in the week the Rays beat Boston twice in their last at-bat to avoid falling out of first place in the division.

The Rays’ game against the New York Yankees on Friday night was rained out and rescheduled as part of a doubleheader today.

Toronto lost for just the second time in 13 games, unable to muster anything against Wakefield (9-10), who was pulled without getting a chance for his first shutout since 1997. Four days after lasting just 1 2-3 innings against Texas, the 42-year-old knuckleballer allowed three hits.

Boston and Toronto also will play two on Saturday to make up for an Aug. 15 rainout. The Red Sox took a six-game lead in the wild-card race over Minnesota, which also was rained out.

David Purcey (3-6) allowed three earned runs and six hits in 6 2-3 innings for Toronto.

Indians 12, Royals 5

Cliff Lee won his 11th straight decision and moved a remarkable 20 games over .500 with his 22nd victory for the Indians.

Unbeaten in 12 starts since July 11, Lee (22-2) allowed four earned runs in 8 1-3 innings to win his eighth straight start. Lee is the first pitcher to have 20 more wins than losses since Oakland’s Bob Welch in 1990.

Jose Guillen homered twice for Kansas City.

Angels 5, Mariners 3

At Anaheim, Calif., Mike Napoli’s two-run homer with two outs in the ninth gave Los Angeles a victory over Seattle.

Napoli homered off Miguel Batista (1-7), who had walked Robb Quinlan with two outs. Napoli drove a 3-1 pitch deep over the fence in left field for his 16th homer and fourth RBI of the game.

Jose Arredondo (8-2) pitched a perfect ninth for Los Angeles.

Although they wrapped up the AL West on Wednesday, the Angels still want to secure home-field advantage throughout the AL playoffs. Their 90-57 record is baseball’s best.

Rangers 7, Athletics 0

At Oakland, Calif., Matt Harrison pitched a five-hitter for his first career shutout and complete game and Texas beat Oakland.

Hank Blalock hit a home run for third consecutive game and Taylor Teagarden also homered for the Rangers, who won their second straight. Texas moved 51⁄2 games ahead of the A’s in its bid to finish second in the AL West.

Harrison (8-3) allowed four hits in the first five innings, retiring 14 of the last 16 batters he faced.

Greg Smith (7-15), coming off one of his best efforts of the season, gave up six runs on seven hits over 5 2-3 innings.