CLEVELAND -- Bronson Arroyo pitched worse and somehow got much better results.
Arroyo (5-7) struck out six and gave up two runs over six innings for the Reds, who took five of six from their interleague and intrastate rivals this season.
The Indians went 6-12 against NL teams and have lost eight of their last 12 overall. Monday, they go to Chicago to open an eight-game trip -- all against AL Central opponents.
It will be the most crucial stretch of the season for the injury-riddled Indians, who have two starting pitchers and three position players from last year's division champions on the disabled list.
"It is going to make it or break it for us," Indians manager Eric Wedge said. "This is what it's all about. These are the teams in front of us and it will tell us what we need to know one way or the other."
More losses could lead general manager Mark Shapiro to decide to dump high-priced veterans -- including free-agent-to-be C.C. Sabathia, the reigning AL Cy Young winner who is coveted by so many clubs.
"We're trying to hold the fort until we get guys back," Sabathia said. "We get some wins, get players back, we're still good."
Edwin Encarnacion, back in the Reds lineup after missing five games with back spasms, hit a two-run homer in a five-run fifth off Aaron Laffey (4-5). Dunn connected off Rick Bauer in the seventh, a 412-foot shot to right that was his 20th of the season and fifth against Cleveland.
Dunn, well known as a streak hitter, hit .300 (6-for-20) with 10 RBI against the Indians.
"When I'm going bad, I'm the worst," said Dunn, who is batting just .224 overall. "Hopefully, I'll eliminate the bad stretches and keep this going."
Arroyo won for the first time in six starts since May 26. Tuesday in Toronto, the right-hander was rocked for 10 runs, including four in the second inning when he didn't get an out. That dropped him to 0-3 with a 10.07 ERA in five starts in June.
"I threw a lot more bad pitches today than I did in Toronto," Arroyo said. "I hung a lot of breaking balls. I got away with a lot. They were popping them up. It shows how strange this game is sometimes.
"After the first inning, (pitching coach) Dick Pole said, 'It must be turning for you. You hung two curveballs and got out of it.' It's a funny game."
Arroyo came in 1-10 with a 5.79 ERA in 14 career interleague starts, and had been 0-4 with a 7.36 ERA in six starts against the AL since joining the Reds in 2006.
Cincinnati broke open a scoreless game in the fifth, getting two singles, two doubles, a run-scoring wild pitch by Laffey and Encarnacion's 13th homer to make it 5-0.
"I was terrible that one inning, had trouble with my mechanics," Laffey said.
Grady Sizemore ruined Arroyo's shutout bid by leading off the sixth with his 19th homer. Another run scored later in the inning when Reds center fielder Jerry Hairston Jr. kicked away a double by Shin-Soo Choo. The error enabled Ben Francisco, who had walked, to score from first base.
Kelly Shoppach had an RBI double in the eighth off Reds reliever Gary Majewski. In the second inning, Shoppach had stood his ground against the 6-foot-6, 275-pound Dunn in a play at the plate.
"I said, 'OK, you're out, is that all you got?' " Shoppach joked after taking shortstop Jhonny Peralta's relay throw and making the tag. "It was a clean play and we really didn't collide."
In the ninth, Encarnacion singled home Phillips, who had doubled off Rafael Betancourt. Phillips had three of the Reds' 14 hits.
Ben Francisco hit his sixth home run, a two-run shot off Jeremy Affeldt with two out in the bottom of the ninth.
Cincinnati opens a seven-game homestand Monday against Pittsburgh after going 5-4 on its first winning trip of the season.
"It means a lot to me," manager Dusty Baker said of the Reds, who have won only two of 22 trips since 2006. "It's been tough. Getting beat on the road doesn't leave a very good taste in your mouth."
Phillips hit .375 (9-for-24) with a homer and six RBI this year against his former team. ... Reds DH Ken Griffey Jr., went 1-for-4 Sunday and is in a 2-for-23 (.087) slump. ... OF Jay Bruce, in a 5-for-23 (.217) slump, and 1B Joey Votto, in a 3-for-19 (.158) skid, were out of the Reds' lineup. ... Javier Valentin, normally a catcher, started at first base for Cincinnati. ... Indians 1B Ryan Garko, hitting .118 (4-for-34) over nine games and OF Franklin Gutierrez, in a 2-for-30 (.067) slide, did not play.