(SportsNetwork.com) - Jeff Locke will try to extend a solid run by Pittsburgh starting pitchers as the Pirates conclude a four-game set with the San Diego Padres on Sunday evening.

Locke halted a six-start winless drought on Tuesday with a 5-1 win over Miami, winning for the first time in three decisions as he blanked the Marlins over 5 2/3 innings. He did walk four, but gave up only four hits and struck out six to earn his first win since April 18. The left-hander moved to 3-2 on the year with a 4.70 earned run average.

Locke struggled in his lone previous start against the Padres, yielding four runs on seven hits and three walks over just five innings. He struck out five in taking the loss.

Pittsburgh's starters have gone 8-0 with a 2.06 ERA and 73 strikeouts over the club's past 10 games, with Charlie Morton extending that run in last night's 5-2 win.

In his second start of the season after opening the year on the disabled list while recovering from hip surgery, Morton yielded two runs -- one earned -- on three hits over seven innings.

"The sinker had really good life," Pirates manager Clint Hurdle said. "In the first inning the adrenaline was flowing. The curveball was sharp. His pace on the mound was very good."

Morton retired the final ten batters he faced, including the final eight on ground balls, and also drove in a run.

"He was on tonight. We just couldn't solve him," Padres manager Bud Black said of Morton.

Tony Watson struck out the side in the eighth and Mark Melancon threw the ninth for his 13th save in Pittsburgh's ninth win in 12 games.

Pittsburgh's top three hitters in the lineup, Josh Harrison, Gregory Polanco and Andrew McCutchen, combined to go 6-for-13 with two RBI and three runs scored.

Tyson Ross surrendered seven hits and three runs -- two earned -- over six innings for the Padres, who had won four of six coming in.

The Padres will look to get a third straight strong showing from right-hander Odrisamer Despaigne, who eyes his first win since April 20.

Despaigne rejoined the rotation in early May and yielded 15 runs and 20 hits over a combined eight innings in back-to-back losses. He righted the ship in a tough-luck 3-0 setback to the Chicago Cubs on May 21, yielding two runs over six frames.

The 28-year-old stayed on track Tuesday against the Los Angeles Angels, logging six scoreless innings of five-hit ball. He didn't walk a batter and fanned five, keeping the Padres in the game before they won 4-0 in extra innings.

The no-decision left Despaigne 2-3 on the year with a 5.23 ERA in 10 games (6 starts). He has never faced the Pirates.

San Diego and Pittsburgh split six games last season and will meet again in the Steel City for three games in July.