CHICAGO -- The emotional swing could be felt at Wrigley Field in the eighth inning Tuesday night. The Padres, after being shut out for seven-plus innings, not only broke through, but suddenly had a lead.

And that perhaps made San Diego’s 3-2 walk-off loss to the Cubs at Wrigley Field even more painful.

Jurickson Profar’s two-run homer off Cubs lefty Shota Imanaga pushed the Padres ahead, 2-1, in the top of the eighth inning. But San Diego’s bullpen, tasked with covering 4 2/3 innings after a solid spot start from Randy Vásquez, faltered late.

“Pitchers' duel and back and forth,” manager Mike Shildt said. “Our guy, Vasquez was really, really good and got us into the fifth. [Adrian] Morejon clearly did his job, and [Stephen] Kolek with a clean seventh.

“Of course, [Imanaga’s] really good, as well. Pitched very well, and we were able to get him right there at the end to take the lead. We clearly gave it right back.”

The Padres had an idea what to expect from Imanaga, who has stymied opponents during a dominant start to his Major League career with his four-seam fastball and splitter combination. He entered Tuesday with a 0.78 ERA and 0.75 WHIP in six career starts.

“He's a pretty good pitcher,” Profar said. “His numbers say it. He's pretty good.”

For seven innings Tuesday, Imanaga was at it again. But when the Cubs sent him back out for an eighth inning of work, with his pitch count at 95, the Padres were ready. Luis Arraez reached on a pinch-hit single to lead off the inning. Profar stepped up, and Imanaga threw him five straight splitters. Profar hit the fifth a Statcast-projected 385 feet for the go-ahead blast.

“The Arraez at-bat really set up my at-bat,” Profar said. “He did a really good job getting on base there.”

San Diego had a chance to tack on an insurance run after Profar went deep. Fernando Tatis Jr. followed the homer with a single but eventually was stranded on third. That soon loomed large.

The Padres’ bullpen had a heavy workload Monday in a series-opening victory, as five relievers combined to throw four innings -- including closer Robert Suarez picking up a five-out save. On Tuesday, Morejon (1 2/3 innings) and Kolek (one inning) kept the Cubs off the board after Vásquez, who started in place of injured starter Joe Musgrove and threw 4 1/3 innings of one-run ball.

Suarez was warming up in the top of the ninth, and Shildt said the Padres would have gone to him only with a lead, after his long outing the night prior.

The manager called on Yuki Matsui in the bottom of the eighth to face the heart of the Cubs’ order. The 2-1 lead gave way to a 2-2 tie in nine pitches. Matsui issued a leadoff walk to Mike Tauchman in a six-pitch sequence.

Jake Cronenworth was holding Tauchman at first base, and he just came up short diving for Cody Bellinger’s ground-ball single to right field. It advanced Tauchman to third base, and he scored moments later on Christopher Morel’s game-tying sac fly. The Cubs won it on Michael Busch's homer off Enyel De Los Santos.

“It's the self-infliction of it,” Shildt said. “It’s the walk that starts it. And then who knows … because he's out of the stretch, if the ground ball’s the same with Bellinger. But Croney’s not holding the bag, and it’s an easy play and possibly the second out.

“We recognize the hard job of the back end of the games, and the lights get a little bit brighter. But the fact of the matter is we just want to make sure we control counts like any pitcher in any situation. And like I said, the leadoff walk was what really basically got us.”

Even in defeat, San Diego was encouraged by Vásquez’s outing, his third with the Padres since he was acquired from the Yankees in the Juan Soto trade. He allowed five hits and one walk while striking out six. The one run he allowed came on Cody Bellinger’s homer in the fourth.

Vásquez got a 50% chase rate on his curveball. ​Entering Tuesday, his career average with that pitch was 33.9%.

“I’ve been able to get more confidence, more trust, in that curveball,” Vásquez said through an interpreter. “... As long as it keeps on working, I know it’ll develop into a good pitch for myself.”