The Frank Schwindel story added another chapter Sunday afternoon at Wrigley Field.

Boy, was it special.

Schwindel hit a grand slam — the third of the game — that sparked the Cubs to a come-from-behind 11-8 win over the Pirates. It gave the Cubs their sixth straight win and a series sweep over Pittsburgh.

“This is just unbelievable,” Schwindel said. “Probably the most fun I’ve ever had playing baseball the last couple of days.”

Trailing 8-7 with 2 outs in the bottom of the 7^th, the cubs loaded the bases and had the right man coming up to the plate in Schwindel. After working the count to 2-2, Schwindel hit a 99-mile-per-hour line drive that just cleared the wall and landed in the left center field basket to give the Cubs the lead.

It’s meant interim manager Andy Green’s comments from Saturday still ring true.

“As long as Frank Schwindel keeps hitting home runs, we’re gonna be OK,” Green said prior to Saturday’s game.

Schwindel has homered in 6 of his last 7 games and the Cubs are 6-1 in those games.

“He’s got a good bat is what’s going on,” Green said. “Frank’s just got this thing on repeat right now and we’re gonna ride it as long as we can and not ask questions about it.”

The heroics of Schwindel partially overshadowed the stellar performance of Matt Duffy. Duffy, who had 1 home run this season entering Sunday’s game, hit a pair of home runs — a solo shot in the 2^nd inning and a grand slam in the 3^rd inning.

“I was just going around all day saying somebody pinch me, somebody pinch me,” Duffy said. 

The Cubs dugout took notice of Duffy’s joy. 

“That was so fun to watch,” Schwindel said. “He came in in the dugout and said something like ‘I’m not even gonna hide the smile and pretend that I’ve done it before because that was awesome.'”

He was 3-for-5 with 5 RBIs and a stolen base. Schwindel and Happ also had 3-hit games in the win.