Manager John Russell can only watch as the Pirates lost a 4-0 decision to the Reds Friday for their fourth defeat in a row.

PITTSBURGH — Two batters faced, two runners on. Bronson Arroyo hadn't gotten an out yet, but he realized he already was at a key point in the game. Turns out the Pittsburgh Pirates were, too.

Arroyo bounced back from his worst start of the season to limit Pittsburgh to four singles over eight innings, a slumping Brandon Phillips homered and the Cincinnati Reds ran the Pirates' scoreless innings streak to 22 with a 4-0 victory Friday night.

Arroyo (4-1) and reliever Francisco Cordero combined to give up five hits, none for extra bases, in the Reds' fourth shutout victory of the season and second in as many games. Edinson Volquez allowed a lone hit over eight innings in beating Houston 3-0 on Wednesday.

The Pirates were shut out for the second straight game, following up a 1-0 loss Wednesday in which Milwaukee winning pitcher Yovani Gallardo homered for the only run. They haven't scored since the fifth inning of a 6-5 loss to the Brewers Tuesday.

"It's one of those things where we're snake bitten with the bats, but it's a long season and the bats will start waking up," said Nyjer Morgan, who had two of the five hits. "We're not distressed about it, it's part of the game you go through."

Arroyo (4-1) allowed eight or more hits in three of his first four starts and was coming off a 10-2 loss to Atlanta on Saturday in which he gave up nine runs and nine hits in 5 2-3 innings, jumping his ERA to 6.48.

The right-hander started off by giving up singles to Morgan and Freddy Sanchez, but got Nate McLouth to ground into one of the two double plays the Reds turned with Arroyo on the mound. McLouth had been out for a week with a rib cage injury. After that, Arroyo didn't permit another hit until the seventh while outpitching Pirates starter Zach Duke (3-2).

The Pirates put the leadoff man on base five times, but never again had multiple runners against Arroyo.

The Reds finally got to Duke on Willy Taveras' double and Joey Votto's run-scoring single in the sixth. Phillips, his average down to .180, hit reliever John Grabow's first pitch of the eighth inning into the right-field seats for his third homer to make it 2-0.

"I felt good out there, had good command, I just got outpitched a little bit — Bronson was really good," said Duke, who reduced his ERA to 2.21 despite losing. "When you're in a game like that, one mistake can hurt you, and I was the one who made a mistake."