MILWAUKEE -- A.J. Burnett might be saving his very best for last.

The 17-year veteran continued his amazing start to the 2015 season Sunday, throwing seven shutout innings as the Pittsburgh Pirates snapped a four-game losing streak with a 3-0 victory over the Chicago Cubs at Wrigley Field.

The Cubs came in having won six in a row but were stopped in their tracks by Burnett (3-1), who allowed three hits while striking out seven in his seven innings of work to earn his third consecutive victory.

"That was just what we needed," Pirates manager Clint Hurdle said. "He pitched with a will to win. He competed very, very well."

He did allow a season-high five walks Sunday, helping ramp up his pitch count, but a nine-pitch sixth inning helped get him over the hump and into the seventh, helping spare a Pittsburgh bullpen still recovering from a 12-inning affair Friday night.

"They stretched some innings out on him," Hurdle said. "He stayed focused. He's really settled into making the next good pitch."

Burnett hasn't allowed more than two earned runs in any of his eight starts this season and has allowed three total over his last four.

"I'm just trying to keep the ball down and not get away from my game, no matter what the guy at the plate is trying to do," Burnett said. "I'm not trying to strike anybody out. Just keep the ball down in the zone where I can be effective."

He worked out of a bases-loaded jam in the fourth as he struck out right fielder Jorge Soler and escaped without damage when left fielder Starling Marte hauled in left fielder Chris Coghlan's fly at the wall in left.

"You have to trust your stuff and your defense," Burnett said. "Great play by Cutch."

Pittsburgh's offense finally gave him the slightest bit of breathing room when third baseman Josh Harrison reached on a one-out bloop double in the fifth, then scored on Francisco Cervelli's single.

"That was a good play, a hustle double," Hurdle said. "We've seen it from him before. That energy, that edge got us on the board first. That was very good to see."

That would be all the Pirates could get off right-hander Jake Arrieta (4-4), who went seven innings and gave up five hits and a walk with seven strikeouts.

"It was a playoff-type of game, from start to finish for the most part," Arrieta said. "The little blooper that Harrison hit that fell in led to their run. Other than that, it was a tight game from start to finish. We had our opportunities but they came out ahead today."

Left-hander Zac Rosscup came on in the eighth for Chicago. He gave up a leadoff single to Cervelli, who scored an insurance run two batters later on second baseman Neil Walker's RBI double.

Walker added another run when he scored on Marte's double, putting the Pirates up a pair.

Chicago brought the tying run to the plate in the ninth, but right-hander Mark Melancon worked out of it for his eighth save of the year.

"We had a chance to tie in the ninth inning again," Cubs manager Joe Maddon said. "We played a great game but they pitched well. Jake was outstanding. They're good. They beat us today. If we have this kind of a homestand the rest of the season, I'll be very pleased."

NOTES: LHP Travis Wood will remain in the Cubs' bullpen for the foreseeable future, manager Joe Maddon said Sunday morning. Wood had allowed 15 earned runs in three starts this month and was 2-2 with a 5.59 ERA this season. ... RHP Tsuyoshi Wada, whose rehab stint at Triple-A Iowa expired Sunday, will start for the Cubs Saturday in San Diego, Maddon said. ... Pirates RHP Vance Worley was available out of the bullpen Sunday. The Pirates are skipping his next scheduled start, which falls within a stretch of two games bookended by off-days. ... Jody Mercer was held out of the starting lineup for a third straight game. Manager Clint Hurdle said he was giving Mercer a mental break as he tries to get past a slow start. Mercer is batting .176 through his first 31 games this season. ... Cubs third baseman Kris Bryant extended his hitting streak to seven games with a first-inning single, but he left the game after four innings due to illness.