CHICAGO (AP) Josh Harrison delivered once again when Pittsburgh needed a big hit. Then he limped off with a left ankle injury that could become a significant problem for the Pirates.
Harrison hit a tiebreaking RBI single in the 11th inning, and Pittsburgh beat the Chicago Cubs 5-3 on Saturday in the conclusion of the series opener that was suspended due to rain.
Harrison finished with four hits and two RBIs, but the All-Star infielder was injured while making an over-the shoulder catch in short center field in the bottom of the 11th inning. He was out of the lineup for the second game.
The Pirates, who are contending for their second consecutive playoff appearance, did not open their clubhouse after they snapped a four-game losing streak. They said Harrison was receiving treatment for discomfort in his ankle and his status would be determined after the second game.
''Very good player,'' Cubs manager Rick Renteria said. ''He seems to be a really gifted baseball player. He does a lot of the little things. He shows you some speed, some pop, some tremendously acute aptitude for the game. And obviously, he's flexible. I mean, they can move him around. He's done well for himself.''
Neil Walker began the 11th with a one-out double off Wesley Wright (0-3), the last of nine Cubs pitchers. Wright then walked rookie Gregory Polanco and pinch-hitter Brent Morel to load the bases before Harrison singled to center. Tony Sanchez added a pinch-hit sacrifice fly.
Mark Melancon (3-4) pitched two scoreless innings for the win and rookie John Holdzkom finished for his first major league save.
Thirteen relievers combined to pitch 14 innings overall, and Wright was the only one to allow any scoring.
''The bullpen did a nice job in general, kept us in there,'' Renteria said. ''We had a couple opportunities we weren't able to cash in on, so tip your hat to them.
''Obviously, we're trying to stay away from as many guys as we possibly could there towards the end. Wesley just had a little hiccup.''
Jose Tabata had two hits and drove in a run for the Pirates.
Chris Valaika had three hits for the Cubs, including a tying RBI single in the fifth.
Harrison helped the Pirates get off to a fast start on Friday. He doubled and scored on a two-out throwing error by third baseman Luis Valbuena in the first. He also had a two-out RBI double in the fourth that gave Pittsburgh a 3-2 lead.
''All in all, I felt the guys kept battling,'' Renteria said. ''We just fell a little short.''
Pirates: RHP Charlie Morton is scheduled to pitch a simulated game on Tuesday. He was placed on the disabled list last month with a sports hernia in his right hip. ''We need some more information before we can make an accurate read,'' manager Clint Hurdle said of his short-term prospects. ... C Russell Martin finished the game after he turned his left ankle on a swing the previous day. Chris Stewart started the nightcap.
Cubs: C Welington Castillo started the second game after he was scratched on Friday due to tightness in his lower back. ... LHP Tsuyoshi Wada, who pitched just 3 1-3 innings on Friday due to mild cramping in his left calf, reported no further problems and was expected to make his next scheduled start.
The Pirates send LHP Francisco Liriano (3-10, 3.91 ERA) to the mound against LHP Felix Doubront (1-0, 1.29 ERA) in Saturday's regularly scheduled game.