CHICAGO — Seth McClung made his second start of the season for the Milwaukee Brewers on Thursday night, and it wasn’t a memorable one.

The big right-hander gave up seven hits and seven earned runs in 31⁄3 innings, paving the way for a 9-5 loss to the Chicago Cubs at Wrigley Field.

“It is disappointing to know that I got an opportunity to show what I could do,” said McClung, who pitched out of the bullpen until recently. “It’s disheartening. I know I’m better than the statistics I put up the last couple of times.”

Derrek Lee hit a grand slam and a three-run home run for a career-high seven RBIs, as the Cubs opened an 11-game homestand with a win over their NL Central rivals.

The Brewers, who entered the game with a one-game lead over St. Louis, are now just a percentage point ahead of the Cardinals, who beat the San Francisco Giants on Thursday.

Lee blasted his 10th career grand slam off Brewers reliever Chris Smith in the fourth inning after connecting for a three-run shot off McClung in the first.

“Just some nights the game seems like it slows down a little bit and tonight was one of those nights,” Lee said.

Jake Fox and Geovany Soto also hit solo homers off McClung (3-2), as Chicago’s erratic offense showed some spark.

“It makes it fun to hit when everyone is swinging the bats well. There are guys on base and pressure on the pitcher,” Lee said. “Tonight is a great night, but we’re right back here tomorrow at 1. ... So, turn the page.”

Cubs starter Ryan Dempster (5-5) got his first win since May 30 and improved his career record against the Brewers to 10-3.

He gave up four runs — three earned — and eight hits in 62⁄3 innings, including Mike Cameron’s 13th homer in the second and Prince Fielder’s 21st in the sixth.

Dempster left after Ryan Braun’s RBI single in the seventh, and Jason Kendall’s RBI single off Aaron Heilman cut the Chicago lead to 9-5 in the eighth.

“Our offense gave us a chance, our starting pitching didn’t,” Brewers manager Ken Macha said. “You’ve got to locate the ball to Lee and we didn’t do it.”

Sam Fuld, replacing slumping outfielder Alfonso Soriano, drew a leadoff walk in the first, Ryan Theriot singled and Lee sent his 13th homer deep into the left field bleachers.

One out later, Fox hit his third home run of the season to give Dempster an early 4-0 cushion.

“This is an important series,” Cubs manager Lou Piniella said. “Derrek has been swinging the bat well now for awhile. You look up there and all of a sudden you see 14 home runs and 48 RBIs and around a .290 (.285) batting average. He’s getting some runs in for us, which is important.”

After Cameron’s two-run drive cut the lead in half, the Cubs drove out McClung with a five-run fourth.

Soto led off with his eighth homer. After a single by Mike Fontenot, a sacrifice and infield single by Fuld, Smith relieved and walked Theriot to load the bases for Lee, who sent another long drive into the left-field bleachers.

“Bases loaded and a 3-1 count is about the best situation you can be in,” Lee said. “He has to throw a strike. He can’t walk you there, so I tried to be aggressive.”

“I’m just swinging the bat well right now,” Lee added. “I’m getting a pitch to hit and putting a swing on it.”

International signing

The Brewers signed Jose Pena, a 16-year-old outfielder from the Dominican Republic on the first day of the international signing period, the Milwaukee Journal
Sentinel reported.

“He’s really a polished kid offensively for 16,” Brewers scouting director Bruce Seid told the Journal Sentinel. “We all liked him, and other teams were interested in him.

“He’s athletic and has some power. He’s got good size, 6-(foot-)3, 195 (pounds), and has a strong enough arm to be a corner outfielder. We really like his make-up. We’re really excited to get him signed.”