CINCINNATI -- With July 4 still a few days off, Eugenio Suarez got an early jump on the fireworks.
Phillip Ervin and Nick Senzel drove in two runs each, and Raisel Iglesias escaped with a six-out save despite allowing Jason Heyward's three-run homer in the ninth. Kyle Schwarber also had a late connection for the Cubs.
Chicago starter Jon Lester (7-6) hadn't lost to the Reds since 2016, a streak of seven straight starts. The Cubs have dropped 3 of 4 and finished June 14-15, their first losing month since May 2017.
"It could've been a lot worse," Chicago manager Joe Maddon said. "We've been a .500 team the entire month."
Yasiel Puig stole two bases a day after a shouting match with Chicago reliever Pedro Strop -- Puig was upset after being hit by a 3-0 pitch. He scored after both stolen bases thanks to Ervin's bloop singles, including one during a four-run eighth. Senzel added a two-run single during the big frame.
"It is always important to add on when you get that chance," Ervin said. "I was up there trying to fight. I tried to fight off good pitches to get something to hit. He just kept throwing good pitches, and I was just fighting them off. Somehow, those two found some grass."
Suarez, hitting .155 over his previous 22 games, blasted Lester's 3-2 pitch a projected 457 feet into a party structure atop the batter's eye in the first inning. The three-run shot gave him 17 homers this season.
"I didn't see where Suarez's drive landed," Bell said. "It never came down. Geno obviously has good power to be able to do that against a good pitcher. It went a long way, but the main thing is it went over the fence."
DeSclafani (5-4) ended his day by striking out David Bote with two runners on and celebrated with a fist pump. He struck out seven and allowed five hits and a walk.
"It was nice to have the lead," DeSclafani said. "I made quality pitches when I needed to. It has been a struggle getting through innings quick and clean."
Schwarber capped a three-run seventh with his 18th homer. Chicago got the potential go-ahead runs to second and third in the eighth before Iglesias coaxed Albert Almora Jr. into an inning-ending foul popup. Heyward's shot in the ninth cut the deficit to two, but Iglesias was able to finish his 14th save.
Lester allowed four runs -- three earned -- on five hits and two walks. He tied his season high with eight strikeouts.
"Their guy pitched better than I did," Lester said. "One pitch doesn't define a start for me."
Despite a game-time temperature of 88 degrees that rose into the low 90s as the game went on, Lester logged a season-high 117 pitches.
Senzel tipped his batting helmet in the direction of Heyward after Heyward leaped above the right field wall to rob him of a two-run homer in the seventh.
The Reds on Sunday wore the sixth of the 15 throwback uniforms they are wearing to celebrate the 150th anniversary of baseball's first all-professional team. Known as "Palm Beach" alternates and worn in 1936, Sunday's outfits featured red pants below white jerseys with "Reds" in script over the heart.
Cubs: SS Javier Baez was given the day off until pinch-hitting in the eighth. He has played in 82 of Chicago's 84 games. ... The Cubs are expected to activate RHP Kyle Hendricks from the 10-day injured list in time to start at Pittsburgh on Tuesday. Hendricks hasn't pitched since June 14 because of right shoulder inflammation.
Cubs: RHP Adbert Alzolay (1-0) makes his third career appearance, second start and first against the Pirates in the opener of a four-game series at Pittsburgh on Monday.
Reds: RHP Tyler Mahle (2-8) makes his third career start and first of the season against Milwaukee on Monday.
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