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Lefty Jeff Locke makes his fourth attempt at a first career defeat of the Los Angeles Dodgers on Friday night when the Pittsburgh Pirates host them in the opener of a three-game weekend series at PNC Park.

A 25-year-old, Locke is unbeaten in his last 10 starts but hasn't actually gotten a win in his last three outings since May 25.

He tossed six innings of scoreless three-hit ball against Milwaukee in that game, just six days after a seven-inning scoreless stint against Houston yielded a 1-0 triumph.

In three games since, the Pirates are 1-2 and have scored six runs while Locke has allowed four runs on 14 hits in 16 2/3 innings.

He's 0-2 in three career meetings with Los Angeles and has posted a bloated 5.73 earned run average against the Dodgers in 11 full innings.

For Los Angeles, righty Stephen Fife makes his fourth start of the season and ninth of a brief big-league career.

A former draft choice of the Boston Red Sox, Fife reached the majors with the Dodgers last season and was 0-2 in five starts.

He debuted this season with a no-decision against Baltimore, then earned his first victory with 5 1/3 innings of one-run ball against San Diego on June 3.

In one subsequent outing, the 26-year-old from Idaho allowed two runs in 6 2/3 innings of a 2-1 loss to Atlanta.

He has never faced the Pirates.

On Thursday in Pittsburgh, Matt Cain pitched 6 2/3 scoreless frames and Hunter Pence hit a three-run homer as the San Francisco Giants crushed the Pirates, 10-0, to salvage a win in the finale of a three-game set.

Pirates starter Charlie Morton (0-1), who had been sidelined for more than a year thanks to right elbow inflammation that eventually required Tommy John surgery, allowed four runs -- two earned -- on seven hits and plunked three over five frames to absorb the loss.

"He did some things well and he's got some areas that I think he'll be able to improve upon," said Pittsburgh manager Clint Hurdle. "I think there was some nervousness in the first inning."

Pittsburgh, which had won four of five coming in, was also looking for its first sweep of San Francisco since May 6-8, 2008.

On Wednesday in Los Angeles, Martin Prado delivered a go-ahead, ground- rule double as part of a four-run 12th inning as the Arizona Diamondbacks edged the Dodgers, 8-6, to win the rubber match of a three-game set.

Cody Ross doubled and Miguel Montero singled to start the frame. Prado's ground-rule double over the left-field wall off Ronald Belisario (3-5) plated the go-ahead run.

Following an intentional walk to load the bases, Brandon League took the mound and surrendered a single to Cliff Pennington that scored Montero.

The Dodgers won six of seven games with the Pirates in 2012 and swept a three- game set this season between April 5-7 in Los Angeles.