PHOENIX -- Pittsburgh second baseman Neil Walker had three hits and two RBIs and left-hander Francisco Liriano pitched 6 1/3 scoreless innings as the Pirates beat the Arizona Diamondbacks 8-0 to complete a three-game sweep Sunday at Chase Field.

Walker's two-run double in the fifth inning gave the Pirates a 4-0 lead off right-hander Jeremy Hellickson, halting the Diamondbacks' streak of consecutive quality starts at nine.

Liriano (1-1) gave up two singles and walked six as the Pirates (11-8) won their fifth straight. He struck out seven and lowered his ERA to 2.22. He has 30 strikeouts in 24 1/3 innings this season.

Arizona (8-10) had one hit after the second inning while losing for the fourth time in five games. The Diamondbacks had two runs and 18 hits in the series and were just 2-for-20 with runners in scoring position.

Pirates right fielder Gregory Polanco had three hits, scored three runs and drove in a run and first baseman Pedro Alvarez had a two-run single in the first inning.

Center fielder Andrew McCutchen broke an 0-for-16 streak with a single and a sacrifice fly.

Catcher Chris Stewart's sacrifice fly in the eighth inning made it 5-0. Polanco, McCutchen and Sean Rodriguez drove in runs in the ninth.

Third baseman Josh Harrison and left fielder Starling Marte each had two of the Pirates' season-high 14 hits.

Left fielder Ender Inciarte and catcher Jordan Pacheco had the Diamondbacks' two hits in the first seven innings, but both were erased on the bases.

Leadoff hitter Inciarte was thrown out at second by Marte while attempting to stretch a single down the line in the first inning. Pacheco singled in the second but was picked off second base when Hellickson missed a bunt attempt.

Hellickson (1-3) gave up seven hits and four runs in 4 2/3 innings. He tied a season high with six strikeouts and walked two.

NOTES: Pirates LHP Francisco Liriano recorded his 77th victory in his 200th career start. He has given up three earned runs or less in each of his last 11 starts since Aug. 25, 2014, and his 1.57 ERA is the best in the majors among starters with at least 60 innings in that span. ... The Pirates' second three-game sweep of the season was their first in Arizona since the Diamondbacks joined the league in 1998. ... The Chase Field roof was open when it was 77 degrees at game time, but then closed when rain began falling in the last of the eighth inning. ... Pirates 2B Walker extended his hitting streak to nine games, halfway to his career-long streak set in 2010.