The Cardinals hoped to put some distance between themselves and the Reds in a four-game series in Cincinnati, but after losing a difficult game on a walk-off homer Wednesday, they won Thursday to salvage a split of the four-game series.
St. Louis rode four home runs -- two by rookie Chris Duncan -- to a 6-1 win Thursday. The Cardinals still lead the Reds by 3 1/2 games in the NL Central, and now the Reds have only three more cracks at the Cardinals, all next week in St. Louis.
"To come back after we got beat (Wednesday) night, that was impressive," Cardinals manager Tony La Russa said.
Rookie right-hander Anthony Reyes survived three hit batsmen to work five scoreless innings for his second consecutive victory. Duncan's homers give him 10 in 137 at-bats this season.
"They switched the momentum on us last night," Spiezio said, "but it's our job to keep our composure and do what we're capable of doing."
The Cards begin a three-game series with the Pittsburgh Pirates on Friday at PNC Park.
The Pirates (42-73) have the worst record in the National League and have dropped seven of nine meetings with the Cardinals (62-52) this season.
St. Louis is just 18-25 against its other four division rivals.
Jeff Suppan (9-6, 4.85 ERA) looks for his fourth win in five starts when he takes the mound for St. Louis on Friday. The right-hander has been nearly flawless since the All-Star break, going 3-1 with a 1.95 ERA in five outings.
He allowed four hits and one run in 7 1-3 innings to defeat Milwaukee 7-1 on Sunday.
Suppan is 1-1 with an 8.00 ERA in two starts against the Pirates this season, but is 7-2 with a 3.61 ERA in 13 career starts against his former team.
Suppan went 10-7 with a 3.57 ERA in 21 starts for Pittsburgh in 2003 before being dealt to Boston.
After being swept by Houston in three games, the Pirates have lost five in a row and are 20 1/2 games behind St. Louis.
Pittsburgh scored only four runs in the series against the Astros and has been held to two runs or fewer in each of its last four contests.
Zach Duke (7-10, 5.35) looks for his first win in four outings when he starts for Pittsburgh. The 23-year-old left-hander beat the Rockies on July 19, but is 0-2 with a 6.75 ERA in three starts since then.
He gave up nine hits and five runs in six innings of a 7-5 loss to the Chicago Cubs on Saturday.
Duke is 1-0 with a 6.55 ERA in two starts against the Cardinals this season. He pitched two scoreless innings against St. Louis as a rookie last year.
REPLAY: Chris Duncan hit two homers, Jim Edmonds one and Scott Spiezio one to account for all but one of the runs in a 6-1 Cardinals victory over the Reds.
Edmonds drove in two runs and had three hits as Anthony Reyes, with help from three relievers, gained his fourth victory in nine decisions.
--The Cardinals have lost 10 of their last 14 games but never saw their division lead shrink lower than 2 1/2 games in that span.
--LF Chris Duncan was 7-for-14 with three home runs in the series at Cincinnati.
--3B Scott Spiezio, who hit three homers in the series at Cincinnati, is 7-for-18 in a six-game hitting streak.
--3B Scott Rolen, who came out in the third inning Wednesday with back spasms, may sit out until Saturday in Pittsburgh.
--CF Jim Edmonds' homer Thursday was his 228th in seven seasons with the Cardinals, tying Ray Lankford for fourth on the club's list. Edmonds hit 121 with the Angels.
--RHP Jason Marquis, though failing to complete four innings in two of his last three starts, is slated to start Sunday at Pittsburgh.
--LHP Mark Mulder, on the rehabilitation trail after recovering from a shoulder impingement, will pitch a for Triple-A Memphis on Friday night. He then may face Cincinnati at home next week.
LHP Ricardo Rincon went on the disabled list retroactive to April 19 with a left shoulder injury. He underwent surgery to repair rotator cuff and impingement problems and will miss the remainder of the season.
OF Larry Bigbie went on the disabled list June 6 with a hernia, and he had surgery on June 8. He started a rehab assignment July 12, but he was shut down July 22 after suffering abdominal pain. He resumed his rehab Aug. 2 with Double-A Springfield.
LHP Mark Mulder went on the disabled list retroactive to June 21 with a left shoulder strain. He made a rehab start for Class A Quad Cities on Aug. 6. He is scheduled to pitch for Triple-A Memphis tonight.
3B Scott Rolen left the game Aug. 9 with upper back spasms, and he didn't play Aug. 10. He's unlikely to play Aug. 11.