PITTSBURGH -- The Cubs had barely put a dent in the line of Paul Skenes, the top pitching prospect in MLB, by the time he had exited his debut with two on and no outs in the top of the fifth inning on Saturday. But they were able to grind out at-bats and patiently wait for their chance to strike.

And when they struck, the outburst took more patience than anyone at PNC Park expected.

The Cubs scored seven runs in one of the most unusual innings you’ll ever see. It took more than three hours, featured six bases-loaded walks and gave the visiting team the lead without much drama, though they eventually fell to the Pirates, 10-9.

It seemed impossible for the Cubs to pull off what they did. Entering the fifth, Chicago trailed 6-1, with Justin Steele having allowed three home runs in four innings. Mike Tauchman doubled to begin the frame and Seiya Suzuki singled to chase Skenes, giving the team a glimmer of hope before Kyle Nicolas trotted in to strike out the first two batters he faced.

All Nicolas needed was one more out.

It never arrived for him.

Nicolas hit Ian Happ with a pitch, then issued three bases-loaded walks to give way to Josh Fleming, who promptly walked Yan Gomes to plate the fourth run of the frame. Between Nicolas and Fleming, the Cubs at one point saw 15 consecutive balls.

A few pitches into Tauchman’s second at-bat of the inning, which came with the tying run on third, lightning flashed and thunder boomed. A severe storm was on the doorstep of PNC Park. Tauchman struck a single to tie the game at 6-6 right before the tarp was rolled out.

It took two hours and 20 minutes for play to resume. By the time the teams returned to the field, Steele had thrown about 20 more pitches in the batting cages to finish his day, two double rainbows had shone above the ballpark and a tornado warning had come and gone south of the city.

“It felt like a doubleheader of sorts,” said shortstop Nico Hoerner. “A lot to break down from a day like that.”

The Cubs didn’t feel any need to be aggressive against reliever Colin Holderman, who took over for Fleming once play resumed with the bases still loaded -- as they had been for what seemed like an eternity. Suzuki walked on four pitches, then Cody Bellinger took one strike before taking Chicago’s sixth bases-loaded free pass of the marathon inning. Nick Madrigal then lined out to center field, bringing to an end the 13-batter inning that set some weird baseball history.

The Cubs’ six bases-loaded walks were the most by an MLB team in one inning since April 22, 1959, when the White Sox had eight in the seventh inning of a 20-6 victory. Since then, no team had ever had more than four in an inning.

“We had good at-bats at the beginning of it to put us in that situation, and then guys weren’t chasing,” Hoerner said. “That’s what it was.”

It’s certainly not a blueprint for long-term success to rely on opposing pitchers to be wild in succession, but it makes for an inning neither the teams nor the fans will forget for a long time, one that kept the Cubs within striking distance until the final out.

“It’s just proof that the game shows you something new every day,” manager Craig Counsell said. "It was a strange inning, and it was a big inning that got us back into the game after a big deficit. We took the lead with some more walks. We just couldn’t hold it.”