Cincinnati ? The only folks who expected such a finish were those five Cincinnati Reds fans who brought brooms.

They waved their brooms in the outfield stands Monday night after Ken Griffey Jr. hit his 491st homer, and Austin Kearns hit a three-run shot in the eighth for a 7-5 victory and a four-game sweep of the Houston Astros.

Kearns’ tiebreaking homer off Brad Lidge (0-3) pushed Cincinnati a half-game ahead of the Chicago Cubs for the NL Central lead.

A club that lost 93 games and traded away stars last season now has the league’s best record, having swept a team counted among the NL’s best.

“Those guys are as good as it gets,” Kearns said, with shaving cream smeared in his hat and shirt after an impromptu celebration. “Just to win the series would have been sweet. To sweep is great. I can’t say enough.”

The Astros had the misfortune to run into a streaking team on its home field.

Cincinnati has won six in a row — its best spurt since 2002 — to grab sole possession of first place for the first time since April 15. The Reds have won nine of 10 overall.

The Astros hadn’t been swept in a four game series since June 24-27, 1999, when the Reds did it in the Astrodome. Houston has lost a season-high five in a row.

“They made all the plays, made all the pitches and got all the calls,” said Craig Biggio, who had a pair of hits. “We’re not sitting here crying over it. They’re hot right now, and when you’re hot, you get everything going your way.”

Griffey hit his second homer in two games, a solo shot that tied him with Fred McGriff for 21st place on the career list. He also had a two-run double off Tim Redding that smacked off the left-field wall, a few feet short of another homer.

Sean Casey also homered for the second straight game and had a pair of hits, raising the NL’s top batting average to .386.

John Riedling (3-0) got the win despite giving up Lance Berkman’s tying, two-run homer in the seventh. Danny Graves got three outs for his major-league-leading 21st save in 25 chances.

Pinch-hitter Jason Lane singled and scored on a passed ball to make it 7-5, but Graves retired Jeff Bagwell and Berkman with a runner at third to end it.

The Reds’ resurgent rotation and an offense led by Griffey and Casey set up the sweep, celebrated by those fans hoisting brooms in the outfield seats.

“The main thing is we’re winning and playing good baseball,” manager Dave Miley said. “But it’s only May. There’s still a lot to play.”

The surge has energized a roster that still has big holes — the bench is thin, the bullpen is shaky — but is overcoming them with good karma.

“We’re a close-knit group,” said Casey, who was 2-for-3 with an intentional walk. “You look out there and feel you want to win for that guy.”

The NL’s top offense was limited to six singles in Cory Lidle’s 7-0 shutout Sunday and was reduced to playing one-base-at-a-time in the first six innings against Jose Acevedo.

The Astros managed only eight singles off Acevedo before Orlando Palmeiro led off the seventh with his second pinch-hit homer of the series, ending Acevedo’s night.

Riedling, who hadn’t given up an earned run in his last 15 appearances, walked Bagwell with two outs in the seventh and gave up Berkman’s homer, his 10th.

Berkman also had an RBI single in the fifth that snapped the Reds’ shutout streak at 13 innings.

Griffey led off the second inning with his 10th homer, a 430-foot drive that smacked off the middle of the batter’s eye in center. Casey led off the fourth with his sixth homer into the Astros’ bullpen.

Marlins 13, D’backs 5

Miami — Juan Pierre drove in four runs, Ramon Castro broke out of a season-long slump with three RBIs, and Florida beat Arizona. The victory was Jack McKeon’s 100th as Marlins manager, and it pulled Florida into a tie with Philadelphia atop the NL East.

Jeff Conine homered, and Carl Pavano (4-2) pitched seven solid innings for the Marlins, who took three of four from Arizona.

Steve Finley hit his major league-leading 14th homer for the Diamondbacks. Brandon Webb (2-4) allowed seven runs and five walks in 51/3 innings.

Braves 5, Expos 0

Montreal — Andruw Jones homered twice, and John Thomson pitched Atlanta past punchless Montreal. J.D. Drew also connected off Zach Day (3-5) for the Braves, who have won four of five following a three-game skid to move within one game of .500.

Playing before only 4,675 fans, Montreal lost its fifth straight. The Expos, an NL-worst 14-30, have been shut out eight times in 44 games.

Thomson (3-2) scattered eight hits through seven innings.