The Pirates have dropped a season-high four games in a row and saw their record fall to .500 after enjoying their second winning April in the past 14 years.

Reds starter Bronson Arroyo (4-1) limited his former team to no runs and four hits in eight innings to outduel Zach Duke (3-2), who lost despite another strong outing.

McLouth, who had missed the past six games with a strained right oblique, went 1 for 4 as part of a tepid Pirates attack. The Pirates haven't scored since the sixth inning of Tuesday's 6-5 loss to the Brewers, a span of 221/3 innings.

During that stretch, the Pirates are batting .096 (7 for 73) with 21 strikeouts and four walks.

Francisco Cordero pitched the ninth inning for his eighth save, striking out Eric Hinske and Andy LaRoche to end the game.

Nyjer Morgan went 2 for 4 to lead the Pirates , who had given Duke an average of 6.0 runs of support in his previous four starts, third best in the NL.

The Reds got an RBI single from Joey Votto in the sixth and Brandon Phillips' solo home run in the seventh on reliever John Grabow's first pitch for a 2-0 lead.

They added two unearned runs in the top of the ninth for a 4-0 lead.

The Pirates' best chance to score came in the first inning, when Morgan and Freddy Sanchez opened the game with consecutive singles, but McLouth grounded into a double play and, after Adam LaRoche walked, Eric Hinske, a lifetime .473 hitter against Arroyo, flied out to the warning track in right field.

No Pirates baserunner advanced past second base the rest of the game.

Arroyo had a lot to do with it. Six days after allowing nine earned runs in a 10-2 loss to the Braves, Arroyo had another strong effort against his former team. He struck out four, walked three and broke at least three bats as he handcuffed the Pirates .

In his past four starts against the Pirates , Arroyo is 2-0 with a 1.44 ERA.

Duke, who has allowed one run or fewer in four of his five starts this season, matched his season high with five strikeouts - out of the first 11 batters he faced - and walked two.

Duke escaped jams in the sixth and seventh innings, getting Alex Gonzalez to ground out with the bases loaded to end the sixth.

In the seventh, the Reds had runners on second and third with one out, but Jerry Hairston popped out to short and Joey Votto, batting .346, grounded to second.

Grabow relieved Duke to open the seventh inning, and Phillips lined his first pitch over the right-field wall for a 2-0 Reds lead.

How they scored

? Reds sixth inning (Zach Duke pitching)

With none out, Willy Taveras hit a ground-rule double to left. Jerry Hairston sacrificed to first, Taveras to third. Joey Votto singled to left-center, Taveras scored.

Reds 1, Pirates 0

? Reds seventh (John Grabow pitching)

With none out, Brandon Phillips homered to right (No. 3) on a 0-0 pitch.

Reds 2, Pirates 0

? Reds ninth (Tyler Yates pitching)

With none out, Ryan Hanigan singled to left. Pinch-hitter Laynce Nix walked, Hanigan to second. Taveras safe on catcher Jason Jaramillo's throwing error, Hanigan scored, Nix to third, Taveras to second. Hairston grounded out to third. Joey Votto intentionally walked. Phillips sacrifice fly to left, Nix scored.

Reds 4, Pirates 0