The Pittsburgh Pirates will try to recapture some lost momentum ahead of next week's All-Star break as they host the New York Mets on Friday night in the opener of a three-game set.

The surprising Pirates led the NL Central prior to a four-game slide that the club snapped with Wednesday's 5-0 victory over the Oakland Athletics. However, thanks to Thursday's loss by St. Louis, the Pirates trail the Cardinals by just a game for the top spot in the standings.

Pittsburgh recorded its first victory in 12 all-time meetings with Oakland on Wednesday thanks to another gem from Francisco Liriano, who hurled seven scoreless innings of four-hit ball. He also struck out six to just one walk.

"The one walk, the six punchouts, just the command of everything tonight," Pirates manager Clint Hurdle said of Liriano. "He was just on top of his game."

Pedro Alvarez, on Thursday named as an injury replacement for Colorado's Carlos Gonzalez in Monday's Home Run Derby, drove in a pair runs, while Jose Tabata finished the game with two hits, two runs scored and an RBI.

Tasked with following Liriano's solid outing will be Charlie Morton, who makes his sixth start of the campaign as he resumes his return from Tommy John surgery.

The right-hander logged a season-high six innings on Saturday versus the Chicago Cubs, but allowed four runs on seven hits and three walks in a loss. Morton yielded a pair of homers in the contest, the first he has given up this season.

"It was a little bit of a mixed bag," Hurdle said of his starter. "He gets two pitches back, I don't know where we are."

Morton, 29, is 1-2 with a 3.38 earned run average this season and is seeking his first career victory over the Mets, who he is 0-2 against lifetime with a 4.50 ERA in five meetings (4 starts).

He'll try to slow down a Mets club that has put together a solid run this month. New York has won four straight, seven of its last 10 and is coming off its first three-game sweep of the season.

That came against the San Francisco Giants, who the Mets bested 7-2 in Wednesday's finale.

Zack Wheeler, drafted sixth overall by the Giants in 2009 before later getting dealt to the Mets in a deal for Carlos Beltran, shut down his former club for six innings before yielding a run in the seventh, his final frame of the night.

"It felt good, I was really looking forward to it," said Wheeler about facing the Giants. "I told the guys earlier I really wanted to do well."

Marlon Byrd, who hit a grand slam in Tuesday's victory, notched a two-run homer in the finale, while John Buck and Daniel Murphy also drove in two runs each.

Right-hander Jeremy Hefner has also found his groove as of late and takes the hill tonight for the Mets.

Hefner has not been charged with more than two earned runs in seven straight starts and is 3-0 over his last five outings. The 27-year-old has logged consecutive seven-inning victories, the latest coming on Sunday in Milwaukee.

He scattered a run on two hits with a walk in eight strikeouts, moving to 4-6 on the year with a 3.39 ERA in 18 games (17 starts).

"He had command of his stuff," Mets manager Terry Collins said of his starter. "He made one bad pitch pretty much the whole game."

Hefner will face the Pirates for the second time in his career, having bested them as a rookie last Sept. 26. He fired seven scoreless innings of three-hit ball in that outing.

The Pirates took three of four when they visited the Mets from May 9-12.