Updated

Milwaukee, WI (SportsNetwork.com) - Chris Stewart smacked a tiebreaking RBI single to spark Pittsburgh's three-run ninth inning and propel the Pirates to a 4-1 win over the Milwaukee Brewers in the middle contest of a three-game set Wednesday at Miller Park.

With the game tied 1-1, Milwaukee closer Francisco Rodriguez (1-1) started the ninth on the mound and lined out Jose Tabata before serving up back-to-back singles to Ike Davis and Jordy Mercer.

"In that situation, you have to find a way to keep the score where it is and give the offense an opportunity," Rodriguez said. "Unfortunately it wasn't my day."

After pinch-runner Clint Barmes replaced Davis, Stewart stroked a single up the middle to score Barmes and Starling Marte followed with a double deep to center, plating Mercer and Stewart for a 4-1 lead.

"He got a pitch and he was able to square it up and hit it hard," Pirates manager Clint Hurdle said of Stewart's tiebreaking single. "It was a big swing of the bat for us."

Mark Melancon worked around a two-out single in the ninth to nail down his fifth save of the season. Tony Watson (4-0) spun a scoreless eighth to pick up the victory.

Pedro Alvarez and Davis collected two hits apiece, while Tabata tallied an RBI to help the Pirates snap a two-game slide.

Jeff Bianchi registered the lone RBI for the Brewers, who had a three-game win streak halted.

Neither starter factored in the decision, despite both hurlers yielding just one run. Milwaukee's Wily Peralta struck out four and scattered five hits over seven frames, while Francisco Liriano fanned seven and allowed just four hits over six innings in the start for Pittsburgh.

The Pirates struck in the fourth, as Andrew McCutchen worked a leadoff walk, moved to third on an Alvarez single through the right side and scored on Tabata's groundout to make it 1-0.

The Brewers broke through in the fifth after Khris Davis clubbed a leadoff double and Jean Segura legged out an infield single to leave runners on the corners for Bianchi, who followed with a sacrifice fly to left, scoring Davis easily to tie the game at 1-1.

Pittsburgh threatened in the eighth after putting runners on the corners with two outs, but Alvarez struck out swinging to leave the potential go-ahead run at third.

Game Notes

Liriano has gone 12 starts since picking up his last victory on Sept. 10, 2013 at Texas ... Milwaukee went 0-for-7 with runners in scoring position and left eight men on base ... Ryan Braun registered two of Milwaukee's six hits in the setback.