(SportsNetwork.com) - The Pittsburgh Pirates eye their fifth straight win on Sunday when they close out a three-game set with the Arizona Diamondbacks at Chase Field.

Pittsburgh continued to roll on Saturday, as Starling Marte's RBI single in the ninth inning lifted the Pirates to a 2-1 win.

Tied at 1-1 with two outs in the final frame, Neil Walker doubled to deep left off Addison Reed (0-1) and came home after Marte hit a grounder past a diving Cliff Pennington at shortstop into left field for an RBI single.

Tony Watson (1-1) earned the win for tossing a scoreless eighth and Mark Melancon followed suit in the ninth for his fifth save of the season.

"You just have to go out and challenge them," Watson said. "Make your pitch and let them put it in play and let our guys do the work behind me."

Pittsburgh hasn't won five in a row in April since 2007.

Tuffy Gosewisch drove in Arizona's lone run with an RBI single and starter Rubby De La Rosa gave up one run and four hits and fanned eight in seven innings of work for the Diamondbacks, who dropped the series opener 4-1.

"He did a nice job tonight," Diamondbacks manager Chip Hale said of De La Rosa. "That's what we expected when we traded for him."

Getting the call for the Bucs on Sunday will be lefty Francisco Liriano, who is 0-1 with a 3.00 ERA. Liriano did not get a decision on Tuesday against Chicago, as he allowed three runs and three hits in five innings of a 9-8 loss.

Liriano has yet to record a decision in two starts versus the D-backs but has pitched to a 3.00 ERA against them.

Arizona will hand the ball to righty Jeremy Hellickson, who picked up his first win his last time out. Hellickson beat the San Francisco Giants last Sunday, holding them to a run in 6 2/3 innings to improve to 1-2, while lowering his ERA to 4.58.

Pittsburgh, which has never swept a three-game set in Arizona, was 4-3 against the D-backs last season.