Anthony Rizzo had a pair of hits on his birthday, Nicholas Castellanos added to his Chicago surge with a pair of homers and the Cubs beat the Cincinnati Reds 12-5 on Thursday night for their biggest NL Central lead of the season.
The Cubs' sixth win in seven games gave them a 3 1/2-game margin over the idle Brewers and a sense that things are heading in the right direction.
Javier Baez unveiled his left-handed swing in the ninth as Kyle Farmer mopped up for the Reds. The Cubs finished with a season-high 19 hits and their first back-to-back games with at least 10 runs since April.
Castellanos had a pair of solo homers among his three hits, the latter breaking a 5-5 tie off Kevin Gausman (3-8) in the fourth inning. He's hit safely in all eight games since the Cubs got him from Detroit.
Ian Happ drove in four runs with a single and a two-run homer, his second straight games with four RBIs.
Hamels returned to the mound where he strained his left oblique on June 28. In his second start off the injury list, a rusty Hamels let an early four-run lead slip away as Aristides Aquino - Yasiel Puig's replacement - had an RBI double and two-run homer .
Aquino's homer was measured at 118.3 mph, tying the Yankees' Gary Sanchez and Mets' Pete Alonso for the hardest-hit homers this season. The International League All-Star was called up to play right field after Puig was traded to Cleveland and has gone 9 for 15 with three homers in his last five games.
Tyler Chatwood (5-1) fanned six in three innings as the Cubs pulled away.
The Cubs signed catcher Jonathan Lucroy on Thursday to help them get through the loss of All-Star Willson Contreras, sidelined by a strained hamstring. Lucroy had three hits and was called for catcher's interference twice.
The Reds fell to eight games out, one shy of their biggest deficit.
Manager David Bell returned from a six-game suspension for going after Pirates manager Clint Hurdle during a benches-clearing brawl last week at Great American Ball Park. Reliever Jared Hughes began a three-game suspension Thursday, imposed for purposely hitting Starling Marte with a pitch. Eight Reds and Pirates were suspended in all, including Hurdle.
Yu Darvish (4-5) is 3-0 in six career starts against the Reds with a 2.92 ERA.
Trevor Bauer (9-8) makes his first start for the Reds at Great American Ball Park. Cincinnati got him from Cleveland in the three-team deal that included Puig. Bauer lasted only 4 2/3 innings of a 5-4 loss at Atlanta on Saturday.