PITTSBURGH -- The Pittsburgh Pirates pitching staff had not allowed a run in 21 innings before Tuesday's game against the Chicago White Sox.

The streak now stands at 30 consecutive scoreless innings after right-hander Charlie Morton pitched seven shutout innings and the Pirates completed a sweep of the White Sox in a two-game series, 3-0 Tuesday at PNC Park.

Pittsburgh's starting pitchers have allowed only five earned runs over the team's last nine games, good for an 0.69 ERA in 65 1/3 innings. Pirates manager Clint Hurdle calls it professional competitiveness as he has witnessed a run of starting pitching he has never seen in his managerial experience.

"Nobody is going to get cut if they don't throw a shutout," Hurdle said. "They're just going out there trying to keep this thing moving."

Pittsburgh moved to a season-high 10 games over .500 with the team's sixth consecutive win.

The Pirates have thrown three consecutive shutouts for the first time since Oct. 2-3, 1976, when they blanked the St. Louis Cardinals on Oct. 2 and in both games of a doubleheader the following day.

Morton (5-0) gave up four hits and walked only one batter. He struck out three and retired 11 batters in a row during the middle innings.

"Anytime you go out there you want a good game," Morton said. "I try not to make that an issue, a factor. I just go out there and try to keep my team in the game."

Chicago center fielder Adam Eaton led the game off with a walk and stole second but was thrown out at third when he overslid the base on a fielder's choice. Shortstop Alexei Ramirez advanced to second on first baseman Jose Abreu's single, but Morton retired left fielder Melky Cabrera and right fielder Avisail Garcia to end the threat.

That was the most trouble Morton faced Tuesday. He cruised through the seventh from there.

"I think I started getting ahead, throwing more strikes," Morton said. "They were pretty aggressive. They were putting a lot of balls in play. That first inning I just wasn't where I want to be."

Pittsburgh started the scoring in the third. Left fielder Starling Marte led off with a single, stole second base and came home on center fielder Andrew McCutchen's single to left for a 1-0 edge.

First baseman Sean Rodriguez doubled the lead with a solo home run in the fourth. Chicago left-hander Jose Quintana hung a curveball over the middle of the plate that Rodriguez sent beyond the wall into the left-field bleachers.

Catcher Francisco Cervelli tacked on a run in the sixth with his second home run of the season. Quintana threw a fastball low but over the middle of the plate that Cervelli hit out to left field, putting the Pirates up 3-0.

Quintana (3-7) gave up three runs and nine hits. He walked one and struck out five.

The left-hander, who infrequently gives up home runs, uncharacteristically gave up two Tuesday night.

"I tried to keep the ball down but they're swinging," Quintana said. "That's going to happen."

Despite a quality start from Quintana, the White Sox never threatened with an offense that failed to score again. Chicago went 6-for-58 (.103) at the plate in two games at PNC Park, a number nowhere near good enough for manager Robin Ventura.

"We just didn't swing it," Ventura said. "(Quintana) gave up a few runs there but if you're going to keep putting up zeros it's tough to win games."

The White Sox advanced their first runner into scoring position since the first inning in the seventh when Garcia reached on a fielder's choice and catcher Geovany Soto singled. Pinch hitter Adam LaRoche grounded into a fielder's choice on the first pitch to end the threat.

Right-hander Mark Melancon worked a scoreless ninth for his 21st save.

NOTES: Pittsburgh announced the signing of first-round compensatory draft pick 3B Ke'Bryan Hayes, the No