CHICAGO -- A go-ahead, seventh-inning grand slam by red-hot Cubs first baseman Frank Schwindel topped off a wild Sunday afternoon at Wrigley Field, leading to an 11-8 Chicago victory over the Pittsburgh Pirates and a four-game sweep.

Schwindel's blast was the third go-ahead slam of the game, including two from Cubs hitters. It's the first time in MLB history a game featured three go-ahead grand slams.

"It's been ridiculous," bench coach and fill-in manager Andy Green said after the game. "You hit two grand slams in a day, you have a good chance at winning a baseball game."

Pirates outfielder Bryan Reynolds hit the first slam of the game, in the top of the third inning, turning a 2-1 deficit into a 5-2 lead. But that was equaled by Cubs second baseman Matt Duffy just a few moments later, when he went deep in the bottom of the third to give the Cubs the lead again.

The Cubs trailed 8-7 in the seesaw affair when Schwindel hit his fourth home run of the month with two outs in the seventh. That came a day after he walked off a victory by sliding safely into first base as the winning run crossed the plate in the ninth inning on Saturday.

"Frank has this thing on repeat, and we'll ride it as long as we can," Green said.

Schwindel is the latest journeyman call-up to make headlines for the new-look Cubs. He's slashing .338/.383/.655 in 32 games after taking over for the departed Anthony Rizzo after the trade deadline.

He has become a bit of a folk hero on a team void of stars for the first time in years.

There's even a debate which nickname fits him best.

"I call him Tank Schwindel," Duffy said. "With his name, I'm sure we can come up with some great ones. Schwindy City is one I saw. That's pretty good. The way he's swinging it, I think Tank Schwindel is all you need."

Before getting called up by the Cubs, the 29-year-old Schwindel had just 35 career plate appearances while playing for Kansas City and Oakland.

He's making the most of his opportunity without thinking about the future.

"That's the last thing on my mind," Schwindel said. "I'm just going to show up and play as hard as I can. ... This is just unbelievable. Probably the most fun I had playing baseball the last couple days."

The three grand slams tied a record for most slams in a game, accomplished four other times in MLB history. Duffy's blast came an inning after he hit a solo shot to get the Cubs on the board. Coming into the game, Duffy had just one home run on the season.

"I said it to [Colin] Moran after my first one, 'If I'm hitting a homer today there's going to be a lot of runs scored,'" Duffy said.

The 4:12 affair featured 23 hits and 14 walks between the two teams. The Cubs had several hitting heroes, but none bigger than Schwindel, who said he's signing autographs and being recognized on the street for the first time in his career.

"My buddies made a bunch of Schwindy City T-shirts," he said. "I heard the Frank the Tanks chants in the crowd. It got loud. It was a lot of fun."

The win was the Cubs' sixth in a row, the past three without manager David Ross due to a positive COVID-19 test. He'll be out another week.