CHICAGO -- Pittsburgh Pirates right-hander Gerrit Cole wanted to make one thing clear after Thursday's 3-2 win against the Chicago White Sox.

Cole's league-leading 11th victory belonged to everyone in the clubhouse, not just himself.

"It's a testament to how well we've played when I take the mound," Cole said. "I take pride in going out there and competing every fifth day. But at the same time, those guys are giving me everything they've got out there. It's more of a team stat than an individual stat."

Name a statistic, and it probably is a good one for the Pirates these days.

Pittsburgh (39-27) extended its season-high winning streak to eight games while completing its eighth series sweep of the season -- the most in the majors. The last time the Pirates won eight consecutive games was from June 26 to July 3, 2004.

Cole (11-2) was the biggest reason for the latest victory. He had command of his fastball, and he used it to limit the White Sox to two runs on three hits. He walked three and struck out four.

Pirates catcher Chris Stewart marveled at Cole's performance on the mound. In his last six starts, Cole is 6-0 with a 1.06 ERA.

"That's special," Stewart said. "He's got tremendous stuff. I think everybody knows that. But I think what has separated him this year from the past is his mentality out there on the mound. He knows how to attack the hitters. He knows when he needs to reach back and get that extra velocity, and he knows when he doesn't need to do it. He makes big pitches in big situations."

The White Sox (28-37) lost their seventh consecutive game and scored just five runs in their past five. The team squandered a quality start by right-hander Jeff Samardzija, who limited the Pirates to two runs in seven innings.

Samardzija remained winless since May 22. He scattered 10 hits while walking none and striking out seven.

"We've got to be able to put up more (runs) than that," White Sox manager Robin Ventura said. "I thought Jeff pitched well tonight. He pitched well enough to win, and their guy pitched well, too. We couldn't get anything going offensively."

White Sox right-hander Jake Petricka (1-2) drew the loss out of the bullpen.

Pirates closer Mark Melancon pitched a scoreless ninth for his 23rd save.

"We're just us," said Pirates second baseman Josh Harrison, who went 2-for-4 with an RBI. "We have fun. We've got a loose clubhouse where everybody pulls for each other. We're having fun enjoying the game."

Pirates right fielder Gregory Polanco drove in the go-ahead run in the eighth inning to make it 3-2. With runners at first and third base and one out, Polanco hit a soft ground ball to the right side of the infield that scored third baseman Jung Ho Kang.

One inning earlier, the White Sox evened the score at 2-2 on a home run by catcher Geovany Soto.

The Pirates grabbed a 1-0 lead in the fourth inning. Kang drove in his 25th run on a sharp ground ball that deflected off Samardzija's glove and rolled free.

The White Sox evened the score at 1 in the bottom of the fourth on a sacrifice fly by left fielder Melky Cabrera that scored first baseman Jose Abreu, who doubled and advanced to third base on a fly ball by designated hitter Adam LaRoche.

Pittsburgh regained a 2-1 edge in the fifth after Samardzija loaded the bases with two singles and a hit batter. Harrison put the Pirates on top with a sacrifice fly to center field.

"It was a battle out there," Samardzija said. "I wanted to come out there and have a good strong outing and give our team a chance to win. Unfortunately, it didn't turn out that way, but we fought out there. We were going against a pretty darn good pitcher there in Cole, who is in his prime. He looks really good."

NOTES: White Sox RHP Scott Carroll was recalled from Triple-A Charlotte before Thursday's game. Carroll, 30, went 1-1 with a 3.12 ERA in eight relief appearances with the White Sox in April and May. He will go to the bullpen as a long reliever and possible spot starter, manager Robin Ventura said. ... Pirates 2B Neil Walker did not start because of a stomach ailment. Teammate Josh Harrison took Walker's place at second base. ... The White Sox designated RHP Hector Noesi for assignment. Noesi, 28, is 0-4 with a 6.89 ERA in 10 games, including five starts. ... Pirates LF Starling Marte returned to the lineup after tweaking his left ankle a day earlier. Marte left Wednesday's game in the ninth inning after appearing to injure the ankle while stepping on first base.