CHICAGO — For the second consecutive day, a pivotal point emerged in the fifth inning of an NL Wild Card Series game at Wrigley Field.

And this one could be a series-defining moment.

The day after Seiya Suzuki and Carson Kelly hit back-to-back homers for the Cubs in the bottom of the fifth, the San Diego Padres stole momentum with two runs in the top half.

We’ll set the scene in Wednesday’s game: The Padres were clinging to a 1-0 lead over the Cubs in Game 2 of the best-of-three series.

Shota Imanaga was on the mound for the Cubs, making his first-ever MLB relief appearance. Padres star third baseman Manny Machado stood in the batter’s box with a runner in scoring position and two outs.

Machado sent Imanaga’s first pitch — an 84-mph splitter that caught too much of the plate — deep into Wrigley’s left field bleachers for a two-run shot that sucked the air out of The Friendly Confines.

It gave the Padres a 3-0 lead and, with the dynamic San Diego bullpen, was a moment that made the game feel out of reach. The score remained the same, as the Padres evened the series with a 3-0 win.

A lot went into that sequence beyond the homer.

For one, the Cubs simply could have walked right-handed-hitting Machado with first base open. That would’ve brought up lefty-hitting Jackson Merrill, which in theory would be a better matchup for Imanaga. He induced a groundout from Merrill to end the frame after the homer.

Cubs manager Craig Counsell explained why he didn’t intentionally walk Machado in that situation.

“Look, the result suggested we should have done something different,” Counsell said. “Really, just confidence in Shota, plain and simple there. I thought he was pitching well. Unfortunately he made a mistake.”

Imanaga didn’t start Wednesday’s game, with the Cubs instead opting for an opener. Right-handed reliever Andrew Kittredge, who worked a perfect eighth in Game 1, drew the start in Game 2.

The thought behind it was to match up Kittredge with the Padres’ top righties — Fernando Tatis Jr. (hitting leadoff) and Machado (batting third). Then Imanaga could follow with the pocket of lefties lower in San Diego’s lineup. Imanaga had a 7.20 first-inning ERA this season and issues with the home run ball, including 12 longballs allowed in his last six regular-season starts.

The Cubs’ strategy didn’t work out as planned, though, as Kittredge allowed a first-inning run on a sacrifice fly. Imanaga then kept the Padres at bay through his first three innings, though he struggled with his command a bit in the fourth.

In the fifth, the top of the Padres’ order was due up again, and the Cubs had righty Michael Soroka warming in the bullpen.

After retiring the No. 9 hitter (catcher Freddy Fermin), Imanaga stayed in the game to again face Tatis. A tough battle ensued before the Padres right fielder ultimately drew a walk.

A sacrifice bunt moved Tatis into scoring position, leaving Imanaga to face Machado with two outs and the game on the line.

Still, Counsell stuck with his guy — his pitcher who started on Opening Day in Tokyo.

The end result put the Cubs in a hole they couldn’t climb out of Wednesday.

Counsell confirmed Soroka was warm and ready in the Cubs’ bullpen, but the manager didn’t want to go to him in that spot.

“We considered walking Machado,” Counsell said. “I wasn’t going to put Soroka in.”

Entering play Wednesday, Machado was just 1-for-9 lifetime against Imanaga with six strikeouts. The one hit, however, was a homer.

“He owned me,” Machado said.

Machado flew out to right to end the third inning in his first at-bat against Imanaga. But he got to the Cubs’ southpaw in the second battle, and now the teams will play a winner-take-all Game 3 on Thursday at Wrigley Field.

What was a best-of-three series essentially turned into a one-game playoff — like the previous wild-card format.