Rookie Junior Lake hit his first career grand slam in Chicago’s five-run first inning and the host Cubs held off the Milwaukee Brewers, 8-5, on Friday.
Lake was 2 for 4 and has five homers since being called up July 19.
The Cubs and Brewers are tied for fourth place in the NL Central at 60-80.
The Cubs jumped on Brewers starter Kyle Lohse (9-9) in the first inning. Nate Schierholtz singled with one out and runners on first and second to drive in the first run. Two batters later, Lake homored on a 1-0 slider.
Carlos Villanueva (5-8) was the winner in relief. Kevin Gregg got the final three outs for his 30th save in 35 chances. Full story for BostonGlobe.com subscribers.