Cubs 4, Brewers 2: Welington Castillo belted a two-run homer among his three RBIs as host Chicago handed Milwaukee its sixth straight loss.

Jacob Turner (5-8) prevailed in his first career start at Wrigley Field after allowing one run and five hits while striking out seven in 6 1/3 innings. Luis Valbuena added a solo home run while two relievers bridged the gap to Hector Rondon, who worked around a one-out single in the ninth inning to earn his 23rd save.

Khris Davis and Gerardo Parra (three hits) hit back-to-back homers for the Brewers, who fell out of first place for the first time since April 5 and trail St. Louis by one game in the National League Central. Jimmy Nelson (2-6) extended his winless streak to five starts after yielding three runs and nine hits in six innings.

Castillo followed Jorge Soler's one-out double in the second with an RBI single to left. The Cubs had runners on first and second with none out in the fourth before Soler hit into a double play, but Castillo salvaged the frame when he belted a 1-2 pitch out to left for his 11th homer of the season.

Davis hit the last pitch Turner threw over the wall in left with one out in the seventh for his 21st homer before Parra belted reliever Blake Parker's first offering out to right for his eighth. Valbuena provided an insurance run in the eighth when he drove Jeremy Jeffress' 1-1 pitch over the wall in center for his 16th homer.

GAME NOTEBOOK: Milwaukee CF Carlos Gomez did not play after injuring his left wrist Sunday and manager Ron Roenicke said he might miss a few days. ... The Brewers have scored 13 runs during their slide, which included a 15-5 loss to San Francisco on Sunday. ... The season series is tied 7-7 after Milwaukee won 36 of the 52 meetings from 2011-13.