PITTSBURGH — Kyle Gibson pitched into the seventh inning in his Phillies debut and got plenty of support as Philadelphia avoided a series sweep by pounding the Pittsburgh Pirates 15-4 on Sunday.

J.T. Realmuto got five of the Phillies’ 20 hits, with two doubles and four RBIs. Bryce Harper hit three of Philadelphia’s nine doubles and Jean Segura doubled twice and drove in three runs.

“It was a lot of fun,” Gibson said. “There’s nothing like pitching in a pennant race and being on a team that’s fighting every single day to get to where you want to be.”

The Phillies got Gibson (7-3) and pitcher Ian Kennedy from Texas in a deadline deal Friday for rookie right-hander Spencer Howard and two other pitching prospects. A first-time All-Star this season, the 33-year-old righty had lost his last three starts for the Rangers, giving up 15 earned runs on 22 hits and 12 walks in 17 1/3 innings.

But Gibson looked fine against the Pirates, allowing two runs on five hits and striking out five in 6 2/3 innings. He retired the first eight batters before walking Pirates pitcher Mitch Keller in the third.

The Phillies, who had lost four of five, are 3 1/2 games back of the first-place New York Mets in the NL East.

“I thought it was really important that we won today’s game,” Philadelphia manager Joe Girardi said. “To come out and be able to put that many hits together, and runs came up and down the lineup, was really important for us moving forward.”

Pittsburgh is 0-8 with a chance to sweep this season.

“We haven’t been able to finish one,” Pirates manager Derek Shelton said. “Winning the first two games of a series is really good. We have to figure out a way to finish it.”

Realmuto had a two-run single as the Phillies scored five times in the eighth.