CHICAGO -- The celebratory mob that engulfed David Bote on the infield Tuesday night was the conclusion the Cubs needed at the end of a long game and a long day. Chicago had been tested, and not only by the Dodgers.

The day that ended with a 4-3 walk-off win and a doubleheader sweep began with multiple roster moves, including three players landing on the injured list. Clayton Kershaw and Trevor Bauer were lined up for Los Angeles. Cubs rookie Keegan Thompson was asked to make his first career start in Game 2.

• Box score

"Defending world champs. Doubleheader," Cubs manager David Ross said. "It's nice to get two in that scenario, and especially when you feel like every little thing was going against us."

That last sentiment applied to the nightcap, which included plenty of offensive shortcomings and a rare blown save by closer Craig Kimbrel. After the Cubs picked up a 7-1 win against Kershaw in Game 1, some Game 2 heroics by Javier Báez (game-tying homer in the eighth) and Bote (walk-off single in the ninth) sealed the sweep.

"Those are two hard-fought wins," Bote said.

Here is a look at three turning points in Chicago's Game 2 victory.

1. Kimbrel finally flinches
Kimbrel left a fastball up and over the plate, and Max Muncy took care of the rest.

With the Cubs clinging to a 1-0 lead in the seventh -- the last regulation inning in the doubleheader -- Muncy sent a Kimbrel pitch soaring high over right field. Jason Heyward’s pursuit ended at the base of the bricks and ivy as the home run rattled in and out of the Wrigley Field basket.

"Deep fly ball high into the wind," Ross said. "You're talking to the Chicago wind at Wrigley and trying to push that thing back; it just didn't. Muncy got enough backspin on that ball."

For Kimbrel, the home run marked the first earned run he allowed since Aug. 29 of last year, ending a streak of 19 consecutive outings with only one unearned run relinquished. The homer was the first blast off Kimbrel since July 31 of last season, when Josh Bell and Colin Moran went back to back for the Pirates.

Between blasts, Kimbrel had a 1.80 ERA with 45 strikeouts collected and 12 hits yielded to 101 batters faced over 27 games.

"Craig's been great for us," Ross said. "I hate that we couldn't push across a few more to give him some insurance there. Craig's been phenomenal for us all year long."

2. El Mago's latest trick
The Cubs forced Bauer out of Tuesday night's game before the end of the fifth inning, but they had trouble cashing in on a pile of baserunners.

Through the game's first seven innings, Chicago's lineup went 0-for-15 with runners in scoring position. That included the red-hot Kris Bryant striking out twice with the bases loaded. The Cubs' only breakthrough off Bauer was a solo blast by Heyward in the fourth.

"Baseball's a funny game," Ross said. "We had a slew of baserunners out there and just couldn't push it through. You've got some of your horses up there with guys on. It's a funny game sometimes."

One of Ross' horses, Báez, was initially out of the starting lineup for the nightcap. He came off the bench late in the game and wound up in the batter's box against reliever Mitch White in the eighth, when the Dodgers had a 3-1 lead.

White fired an elevated fastball in a 1-0 count and Báez hit a low liner scorching toward left field.

"I was just kind of pushing it out with my mind," Báez said. "I knew I hit it pretty good, so I was just hoping that it went over the fence."

It did, sending the Cubs' dugout and the Wrigley Field faithful into a frenzy as the game was deadlocked at 3-3.

"It was insane," Cubs outfielder Joc Pederson said. "Javy continues to come through in the big moments, and it's fun to watch. The whole stadium was behind it -- a ton of energy."

3. Nerves of Steele
Both Thompson (with 3 2/3 shutout innings) and lefty Justin Steele (scoreless ninth) spent last season training at the Cubs' alternate training site. On Opening Day in the Minor Leagues on Tuesday, both were in the Majors, playing a key role in the twin-bill sweep of the defending champions.

"It's pretty big for them to come in situations like this," Báez said. "It's good for the end of the year and if you go into the playoffs; hopefully they got that experience."

One of the game's most important moments arrived for Steele.

With two outs and two runners on, Steele spun a 2-2 slider that started outside before breaking toward the bottom outer edge of the strike zone. Austin Barnes swung and missed and Steele came off the mound yelling, pounding his chest and slapping his glove.

It was a crucial out that set up Bote's game-winning hit.

"Justin Steele, what a performance," Ross said. "A youngster getting thrown in to the defending world champs in extra innings. That was a big league performance by Justin. That was nice to see."