CINCINNATI -- The Washington Nationals were the hottest team in baseball coming into this weekend's series in Cincinnati, having won 21 of 27. But lackluster starting pitching and a couple bullpen meltdowns resulted in the Nationals being swept for the first time since April.

Todd Frazier and Brandon Phillips homered, helping the Cincinnati Reds complete the three-game sweep of first-place Washington with an 8-2 victory on Sunday afternoon at Great American Ball Park.

The Nationals (28-22) were swept for the first time since April 24-26 at Miami, and by a Reds club that had dropped 10 of 11 coming in.

"The bullpen's been pushed a lot on this trip," said Nats manager Matt Williams. "It would help if your starters go deep into games. That didn't happen much on this road trip. It's a little blip."

Cincinnati (22-27), meanwhile, is brimming with confidence after sweeping Washington for the first time since 2011.

"I wish we didn't have an off-day (Monday in Philadelphia), let's get back out and keep playing," said Frazier, who went 3-for-4 with a homer, double and three RBIs. "We showed a lot of energy, a no back-down mentality."

The injury-riddled Nationals got some good news when right fielder Bryce Harper returned to the lineup after being scratched from Saturday's start with a sore back. He went 0-for-2 on Sunday with two walks.

Reds right-hander J.J. Hoover (4-0) earned the win Sunday.

Nationals right-hander Aaron Barrett (3-1) got the loss after allowing two runs and two hits in one-third of an inning.

"He isn't finding the zone enough, and when he does, the ball is up," said Williams, of Barrett.

The defense shined for Cincinnati in the second inning.

First, shortstop Zack Cozart made a diving stab of catcher Wilson Ramos' liner.

Then Nats left fielder Michael Taylor was thrown out at home attempting to score from first on starting pitcher Tanner Roark's double to center.

Roark didn't allow a hit until Frazier's solo shot on a 2-2 pitching leading off the fourth. It was the Reds' third baseman's 16th home run this season, fourth in six games.

"Hitting is contagious, it's true," Frazier said. "We attacked the ball. We know what we're capable of."

Second baseman Phillips homered for the third time this season in the fifth, making the score 2-0. His first homer since May 17 snapped an 0-for-18 skid.

Roark allowed two earned runs and four hits in six innings.

Roark's double was the only hit allowed by Reds starter Michael Lorenzen, who retired 12 straight before running into difficulty in the seventh.

Lorenzen, the third rookie to start for Cincinnati in the series, allowed two earned runs and issued six walks, three of which came in the seventh to load the bases with one out.

Hoover came on and allowed Taylor's two-run single. He went 1-for-2 with a walk and two RBIs.

"I thought I made some really good pitches," said Lorenzen. "Some of them were just off the plate. I wanted to stay in the game, who doesn't? We competed our butts off this weekend."

Pinch hitter Clint Robinson lined out to first baseman Joey Votto, who stepped on first for an inning-ending double play, keeping the score tied 2-2.

Just as they did throughout this series, Cincinnati roared right back.

Center fielder Billy Hamilton reached on a fielder's choice, stole his 21st base and then scored on Phillips' single, putting the Reds ahead 3-2.

Phillips went 2-for-4 with a homer and two RBIs.

Back-to-back RBI doubles by Frazier and right fielder Jay Bruce off left-hander Matt Grace made the score 6-2. Grace didn't retire a batter and allowed three hits and four runs.

"I'm just not making pitches," said Grace. "That's the bottom line. It all has to do with location. I'm not gettin