PITTSBURGH — J.A. Happ gave up seven runs in his last start with the Seattle Mariners on Thursday, which further endangered his spot in the rotation. He remains a starter, but not with Seattle.

A.J. Burnett’s elbow injury compelled the Pittsburgh Pirates to trade for Happ as emergency rotation depth at last week’s deadline. Happ’s recent struggles followed him to Pittsburgh.

Happ allowed four runs in 4 1-3 innings and the Chicago Cubs beat the Pirates 5-0 in the lefty’s Pittsburgh debut.

“Obviously I would’ve liked to have it gone a lot differently but I just didn’t execute a few key times,” Happ said. “They made me pay for it.”

Chicago tagged Happ (4-7) for eight hits as he walked two and struck out six. The lefty was 0-1 with a 9.00 ERA in his last four starts with the Mariners.

Pittsburgh manager Clint Hurdle said his starter needs to find consistency after he had some good pitch sequences against hitters.

“But overall, balls were up,” Hurdle said. “Balls were up over the plate (with) some deep counts.”

Jake Arrieta pitched seven strong innings for the Cubs and Anthony Rizzo tied a career high with four hits. Chicago won its sixth straight game.

Arrieta (12-6) allowed two singles — Andrew McCutchen in the fourth and Starling Marte in the seventh — while striking out five and walking three.

“I was just being conscious of not giving them much to hit,” Arrieta said. “I had that mindset of not giving in throughout the game.”

Tommy Hunter and Justin Grimm completed the three-hitter with one inning each as the Cubs (58-47) matched their longest winning streak of the season from May 11-16 and moved 11 games over .500 for the first time since the end of the 2008 season.

In his last nine starts, Arrieta is 6-1 with a 1.38 ERA. He improved to 5-1 in his career against the Pirates.

“The cut fastball played well,” Hurdle said.