There is a chance the St. Louis Cardinals could be alone in first place in the NL Central for the first time by the end of Sunday.
In order for that to happen, they'll have to capture this three-game road series against the Philadelphia Phillies by posting a ninth win in 11 games.
St. Louis (70-58) won 6-5 in 12 innings on Saturday to even this series and pull within one-half game of first-place Milwaukee. A Cardinals win Sunday and a Brewers loss to Pittsburgh would give the defending Central champions sole possession of the division lead for the first time.
Matt Carpenter hit a winning sacrifice fly in the 12th inning and Jhonny Peralta homered for St. Louis, which blew a two-run eighth-inning lead. It last held a share of first place July 20.
''It would have been a tough one to lose,'' manager Mike Matheny said. ''It was one of those tough ones to swallow. But the guys fought hard and kept coming.''
Carpenter and Kolten Wong each has gone 4 for 10 in this series, which Philadelphia (57-72) opened by rallying from a three-run deficit for a 5-4 victory Friday.
These two games have kept with the low-scoring theme of a season series that has seen these clubs split six matchups. The Phillies have outscored the Cardinals 23-21 with neither team scoring more than the six runs.
St. Louis will give Justin Masterson (2-1, 6.30 ERA) his fifth start with the club since it acquired him July 30 from Cleveland. He allowed four runs over five innings Monday in a 6-5, 10-inning home win over Cincinnati.
The right-hander went 1-0 with a 2.16 ERA in three starts against the Phillies between 2008-09. He has plenty of experience against center fielder Ben Revere, who is 6 for 29 versus him but hitting .358 in his last 17 games.
The Phillies will also use a starter who wasn't with them at the beginning of 2014 in Jerome Williams (1-0, 2.19), who makes his third start with the club since he was acquired off waivers Aug. 10. Williams yielded one run and three hits in seven-plus innings to win his home debut 4-1 over Seattle on Monday.
The journeyman right-hander, who also spent time with Houston and Texas this year, credited catcher Carlos Ruiz for his role in the strong effort.
"I'm doing things I haven't done before because he has confidence in me," Williams said. "My game plan wasn't working this year. That's why I'm on my third team. We're just using the same weapons, but moving the ball around."
Williams has failed to get out of the second inning in his last two starts against St. Louis, yielding seven runs both times, albeit seven years apart in 2006 and 2013. A.J. Pierzynski has faced him the most among the Cardinals, going 3 for 17.
Pierzynski went 1 for 5 on Saturday although the catcher may give way to Tony Cruz, who was 0 for 3 on Friday.
Ruiz is 4 for 9 in this series and was one of two Phillies with two RBIs Saturday along with Marlon Byrd.