When the two clashed Tuesday night, Suarez prevailed.
Suarez hit a two-run, opposite-field home run to right in the first inning, and two batters later, Jesse Winker followed with his own two-run homer as the Reds routed the Brewers 14-6.
"Who we're playing doesn't matter," Milwaukee manager Craig Counsell said. "You've got to play a good game to win. And we're not playing well enough in these games. We didn't come close to playing well enough tonight."
Davies (8-3) had not allowed a home run since June 25, going 1-0 in four starts since, but allowed six earned runs and nine hits in four-plus innings. His ERA rose from 2.79, sixth-lowest among qualified pitchers, to 3.17.
"He's very patient, aggressive when he needs to be, but stays within the zone," Davies said of Suarez. "He's a tough out. Good swing, strong guy. You can make your pitch and he can still be able to get a hit out of it."
Suarez's homer was his 27th. He leads the major leagues with 10 home runs in the first inning.
"When you face a guy a lot, you know how they pitch and you've got to be prepared. Today, we were really ready for him," Suarez said of Davies. "Everybody knows he's got really good stuff. Really good sinker, change-up, cutter, curveball. But today, he threw a lot of sinkers and we were ready."
"It was tough in one respect in that Jesse is swinging the bat really well right now," manager David Bell said of replacing Winker with Ervin. "On the other hand, we have an opportunity to do what Phil ends up doing. It's just so important in these games to keep adding on. We had the edge right there for Phil with the left-hander. Just trying to take advantage of the matchup."
Tanner Roark (6-6) gave up two runs and six hits in five innings.
Sal Romano, who was recalled from Triple-A Louisville on Monday, made his first appearance of the season and earned a save by pitching three innings, giving up one run.
Manny Pina hit a three-run home run and had four RBI for the Brewers.
Reds: C Tucker Barnhart (right oblique strain) is expected to start a rehab assignment with Triple-A Louisville on Thursday. ... RHP Jesus Reyes, designated for assignment on Thursday, cleared waivers and has been sent outright to Louisville.
Brewers: All-Star RHP Brandon Woodruff on possibly being out six weeks with a left oblique strain: "It's a slow process, but you can't rush it."
The grand slams hit by the Brewers' Tyler Saladino on Sunday and Monday made him the first player to hit grand slams in consecutive games since the Yankees' Jorge Posada in 2010.
The Reds' win on Monday marked the first time this season Milwaukee lost when leading after eight innings (48-1).
Reds manager David Bell on Michael Lorenzen pitching and playing left and right field on Monday: "Michael loves it. He's up for it. The more he's challenged, the better he is."
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