Matt Murton’s RBI single in the eighth inning gave the Chicago Cubs a 2-1 victory over the Pittsburgh Pirates on Monday night.

With the score tied 1-1, John Grabow (0-1) issued a two-out walk to Todd Walker. Salomon Torres replaced him and gave up an infield single to Aramis Ramirez. Murton then singled up the middle past a diving Jack Wilson to score Jerry Hairston Jr, who was running for Walker, from second.

The Pirates dropped to 1-13 on the road and 7-20 overall.

Bob Howry (2-0), the second of three Chicago pitchers, worked 2-3 of an inning for the win. Ryan Dempster pitched the ninth for his seventh save in as many chances. He extended his club record to 25 straight, dating to last season.

Cubs rookie starter Sean Marshall gave up just one hit in his first six innings, throwing 57 pitches in that span. The 6-foot-7 Marshall, trying to start 3-0, gave up one run and four hits in 7 1-3 innings, his longest outing of the season. He struck out five, walked one and threw 91 pitches.

Wilson and Jason Bay hit consecutive singles to lead off the seventh for the Pirates. Wilson moved to third by seemingly avoiding third baseman Ramirez’s tag on a grounder by Craig Wilson. Ramirez thought he tagged Jack Wilson with his glove and threw Bay out at second.

After arguments from Ramirez and Cubs manager Dusty Baker, Wilson then scored on a groundout from Joe Randa to tie the game at 1-1.

Marshall walked Ronny Paulino and Jose Castillo before striking out pinch-hitter Chris Duffy in the eighth. Marshall left a standing ovation.

Juan Pierre led off the Cubs’ first with a single, stole second and scored when Pirates starter Victor Santos committed a throwing error on Ronny Cedeno’s bunt.

Santos gave up five hits and one unearned run in seven innings. He struck out six, walked one and hit a batter.

Notes: Before the game the Cubs recalled LHP Rich Hill from Triple-A Iowa to take Glendon Rusch’s spot in the starting rotation. Rusch is 1-4 with an 8.46 ERA in five starts and will move to the bullpen. … The Cubs sent RHP David Aardsma to Triple-A Iowa. The reliever was 1-0 with a 10.50 ERA in four appearances. … Cedeno was thrown out stealing second in the first inning, after getting picked off first Sunday. … Santos went six innings in a 4-0 loss to St. Louis on April 19. … Frank Castillo in 1991 was the last Cub rookie starter to start 3-0. Castillo lost his next start.

Reds 6, Cardinals 1

At Cincinnati, Bronson Arroyo stayed unbeaten in Cincinnati by pitching a four-hitter for the second complete game of his career, and the Reds beat the St. Louis Cardinals in a matchup of the NL’s top two teams.

Cincinnati set a club record with 17 victories in April and started a new month with the same winning formula — a lot of offense, a little dazzling pitching.

Rich Aurilia hit a solo homer and Felipe Lopez drove in three runs for Cincinnati. Every Reds starter except Arroyo had a hit off left-hander Mark Mulder (2-1), who was denied his 100th career win.

The biggest change in the Reds is the addition of Arroyo (5-0), who has dramatically improved a rotation that was the NL’s worst last season. The right-hander is the first Reds starter to win his first five decisions since Paul Wilson went 7-0 in 2004.

Arroyo extended the best start of his career by limiting the Cardinals to Juan Encarnacion’s solo homer, three other harmless hits and three walks. His only other complete game was for Pittsburgh on Oct. 2, 2001, against the Mets.

Arroyo also became the first Reds pitcher to go eight innings in three consecutive starts since Jose Rijo in 1994.

The victory left Cincinnati (18-8) in sole possession of first place in the NL Central, a game ahead of the defending champion Cardinals.

Arroyo did his best work against Albert Pujols, who had his way with the Reds during a three-homer game April 14 in St. Louis. Pujols leads the majors with 14 homers, a record for April.

This time, Pujols flied out twice, popped out and walked, leaving it up to the rest of the Cardinals’ lineup to prove itself. With their big hitter held in check, the Cardinals had no chance.

Arroyo has been the Reds’ best starter by far, making new general manager Wayne Krivsky’s first major move look good. Cincinnati got the right-hander from Boston for outfielder Wily Mo Pena on March 20.

Arroyo allowed only one hit in eight innings of a 5-0 victory in Washington on Wednesday. He extended his streak of scoreless innings to 16 before Encarnacion hit a solo homer into the upper deck in left field in the second inning, his second homer in two games.

Aurilia’s fifth homer barely cleared the right-field wall in the first inning and got the Reds’ offense rolling. Lopez’s two-out, run-scoring single put the Reds up 2-1 in the fifth and snapped the shortstop’s 0-for-17 slump. His bases-loaded single in the sixth off Josh Hancock completed a four-run rally that put the Reds in control.