Rookie Junior Lake hit his first major league homer and drove in three runs to power the Chicago Cubs to a 4-2 victory over the Arizona Diamondbacks.
Lake's two-run homer off Tyler Skaggs with no outs in the fifth inning gave the Cubs a 3-0 lead. Lake's RBI single in the ninth scored Darwin Barney with an insurance run.
Dioner Navarro hit a solo home run in the second for the Cubs.
The loss, coupled with the Los Angeles Dodgers' win in Toronto on Monday night, dropped the Diamondbacks out of first place in National League West.
They held or shared the division's top spot since May 15. Arizona has lost four of its last five.
Chris Rusin (1-0) got the win, and Kevin Gregg pitched the ninth for his 19th save.
Skaggs (2-2) took the loss.