CHICAGO – A sweet sweep for the Chicago Cubs in their first-place showdown with the crosstown White Sox.

Ryan Dempster won his ninth straight this season at Wrigley Field and Eric Patterson and Aramis Ramirez homered in the same inning for the Cubs, who beat the White Sox 7-1 to finish off the three-game sweep Sunday night.

The Cubs, the owners of the best record in the majors (48-28), won their 14th straight home game to go 32-8 at Wrigley Field this season.

Dempster (9-2), who moved from closer back to starter this season, allowed 10 hits and a run in eight-plus innings, leaving after giving up back-to-back singles in the ninth. He walked one and struck out four.

Patterson, who recorded three hits Saturday when he was recalled from the minors, hit his first major league homer, a two-run shot off Javier Vazquez (7-6) in the fifth to give the Cubs a 4-0 lead.

One out later, the hot-swinging Ramirez connected on his fourth homer of the series, a solo shot. Ramirez hit the tying and winning homers in the Cubs’ 4-3 victory on Friday. He also delivered a three-run homer during a nine-run fourth inning Saturday to spark an 11-7 win.

Ramirez added an RBI double in the seventh inning Sunday and finished the series 6-for-13 with eight RBIs.

Trailing 5-0, the White Sox ended the shutout in the seventh on Jermaine Dye’s double and RBI single from Joe Crede.

The Cubs turned three double plays in the first five innings behind Dempster, including one on the White Sox’s hottest hitter, Dye, in the first after a pair of singles. Dye had six homers and 15 RBIs in his previous six games.

Vazquez couldn’t find the strike zone in the first, walking Kosuke Fukudome and Patterson on eight pitches. Then on a hit-and-run, Derrek Lee singled to center to score Fukudome, and Patterson also crossed when shortstop Orlando Cabrera mishandled the throw from center fielder DeWayne Wise for an error.

Vazquez allowed five hits and five runs with five walks and four strikeouts in six innings.

The White Sox, who have lost 8 of 12 overall and had their lead in the AL Central over the Twins chopped to 11/2 games, didn’t win a game this weekend.

White Sox manager Ozzie Guillen told reporters there were rats as big as pigs in the batting cage; pitcher John Danks said Wrigley smelled of urine; and catcher A.J. Pierzynski, who is always booed loudly, weighed in after fans directed a profane chant in his direction Saturday.

“They’re idiots,” Pierzynski told the Chicago Sun-Times. “It’s like what Lee Elia said: ‘Eighty-five percent of the people work, the other (bleeps) come out here.”‘ Elia was a former Cubs manager, most well-known for an expletive-filled rant against Cubs’ fans 25 years ago.

Cubs manager Lou Piniella is 8-1 and has won six straight against the White Sox in his two seasons on the North Side.

“Put it this way, I’ve only been in town for a year and half and I certainly enjoy the competition against the White Sox, but I don’t go crazy over it,” Piniella said.