MILWAUKEE -- The frustration continues for Marco Estrada.

The Milwaukee right-hander gave up three home runs Sunday, including a game-opening homer by Billy Hamilton and a two-run shot by Todd Frazier that broke a 3-3 tie in the fifth inning as the Cincinnati Reds ran away with a 13-4 victory over the National League Central-leading Brewers at Miller Park on Sunday.

"We had a lot of great two-strike at-bats," Reds manager Bryan Price said. "We got Estrada's pitch count up. It wasn't necessarily his ineffectiveness but our guys grinding out at-bats, one after another."

It was a bad day all-around for the Brewers' pitching staff. Aside from Estrada's ongoing struggles, right-handers Rob Wooten and Mike Fiers let Cincinnati blow the game open with five runs in the ninth inning.

"(Brandon) Kintzler threw the ball well, and (Tom) Gorzelanny threw the ball well," Brewers manager Ron Roenicke said. "Other than that, we struggled."

Estrada's problems, though, are of the utmost concern. He leads the league with 23 home runs allowed this season, and his rate of 2.46 homers per nine innings is by far the highest in baseball.

Of the 35 earned runs Estrada has allowed this season, 25 came via the long ball.

"To be honest with you, it was tough about a month ago but today, mentally, physically, was probably the best I've felt," said Estrada (5-4), who said he had been dealing with some mental issues but didn't go into detail. "I went out there in the first inning and I was trying too hard, way too hard. Mentally I felt great.

"I think I just tried way too hard, and that's what happens. I was rushing stuff, leaving balls up and got hit around. Once that inning was over, I came back in and calmed down."

Despite the Reds' home runs, Milwaukee was able to stay in the game.

Cincinnati scored three times in the first on the home run by center fielder Hamilton and a two-run homer by second baseman Brandon Phillips. The Reds still led 3-0 before Estrada put the Brewers on the board with an RBI single in the fourth. Milwaukee second baseman Scooter Gennett followed with a two-run double down the line in left, tying the game.

The Brewers' momentum didn't last long.

Hamilton led off the Reds' fifth with a base hit, and he scored when Frazier, the Cincinnati third baseman, ripped an 0-1 fastball to left-center for his 15th home run of the year.

Estrada worked through the rest of the inning unscathed and gave way to Gorzelanny for the start of the sixth. The Milwaukee starter allowed five runs on eight hits with three strikeouts.

Catcher Jonathan Lucroy got the Brewers within 5-4 with a solo home run in the bottom of the inning, but after Gorzelanny kept the Reds off the board in his first action of the season and Kintzler did the same in the seventh, Cincinnati heated up in the eighth.

Wooten gave up six consecutive singles to make it an 8-4 game. Fiers was next, and in his 2014 debut, he got Frazier on a called third strike for the inning's first out before issuing a bases-loaded walk to Votto.

"The add-on runs, what it does for you is it allows you to not have to get your (relievers) up," Price said. "We had (Jonathan) Broxton up, and it saved us from having to use him and getting (Aroldis) Chapman up at all. Hopefully, that will pay dividends in Pittsburgh (in the series that starts Tuesday)."

All that offense took the focus off Reds right-hander Mike Leake, who was tagged for four runs on nine hits and three walks in five innings. He pitched well enough to record his second victory in his past 10 starts.

"Our relievers and our offense did a great job today," Leake said. "I did what I could, but our offense really came around today."

The Reds won two of three over the weekend to take their second series of the season from the Brewers, who saw their lead over the division drop to 3 1/2 games the second-place St. Louis Cardinals. Cincinnati (33-35) won for the fourth time in five games and climbed within seven games of Milwaukee.

"It was important," said Price, whose team is 5-2 against Milwaukee this season. "To lose three would have taken us from eight back to 11, and that would put us in a pretty drastic situation in the middle of June. It was definitely big. We're establishing the fact that we can play this team very well."

The Brewers (41-29) and Reds meet 12 more times this season, including six times during the final month.

NOTES: The Reds set a season-high with 19 hits and tied a season-high with five runs scored in an inning. ... Brewers RHP Wily Peralta rejoined the team after dealing with an undisclosed family matter in his native Dominican Republic. Peralta will start the opener of a four-game series at Arizona on Monday.