CHICAGO -- Maybe it looked like a fastball heading to the bottom of the strike zone. Whatever José Abreu thought initially, the White Sox slugger quickly regretted his decision, trying to stop his swing as Craig Kimbrel's curveball dove to the dirt.

There was no halting the momentum of the bat, and Kimbrel had notched his final strikeout of the 2020 regular season. That deceptive breaking ball was paired with a 99 mph heater on Saturday night in a display that would look just fine for the Cubs under the October lights.

"That stuff was explosive and as good as we've seen all year long," Cubs president of baseball operations Theo Epstein said. "The arc of his season is putting him in a really good place to, I think, be a dominant guy in October."

It was quite a journey for Kimbrel to reach that point this season.

Coming off a turbulent season last year, it was evident early on that Kimbrel was not right coming out of Summer Camp. His mechanics were out of whack, his velocity was down and all the issues from 2019 seemed to be plaguing the high-priced closer once again.

Cubs manager David Ross, who trusted Jeremy Jeffress and Rowan Wick early in the season to buy Kimbrel time to work on getting right, noted that baseball's active saves leader was dealing with more than baseball, too. As the COVID-19 pandemic impacted this season, Kimbrel also had to keep his young daughter in mind, given her history of heart complications.

Ross praised Kimbrel for never becoming overwhelmed by the many layers involved in the pitcher's year.

"I was trying to look back on some things that I was most proud of this year," Ross said on Tuesday. "That's one of them. The way that Craig handled the environment that he was presented with, along with having some issues with his daughter in this environment.

"Still coming to work and overcoming a lot of adversity off the field, and then coming here and overcoming on the field -- I mean, this guy had a lot of pressure on him."

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Kimbrel's first opportunity to move on from his disastrous 2019 arrived on July 27 in Cincinnati. The right-hander took the mound in the ninth inning with the Cubs holding an 8-5 lead, and things quickly collapsed. Kimbrel walked four, hit a batter, threw a wild pitch and needed Jeffress to enter to bail him out.

Over Kimbrel's first four appearances, he allowed seven runs and had more walks (five) than strikeouts (two). Opposing batters never flinched at the curve, swinging only twice at the 30 he threw in that stretch. Only one resulted in a whiff. That helped batters hit .500 with a 1.250 slugging percentage off his fastball.

"He never hung his head," Ross said. "The phone rang down there, and other peoples' name was called when it's his time to get that call -- [even with] his résumé. And for him to continue to work and never be [ticked] and never put blame or make excuses -- all he did was come in and go to work, and that's a true professional. That's a man of character."

In the 14 appearances after that rough start, Kimbrel turned in a 1.42 ERA in 12 2/3 innings, holding batters to a .342 OPS. He had 26 strikeouts among the 49 batters he faced in that run. That included 14 whiffs out of 29 swings on 83 curves thrown. The batting average (.045) and slugging percentage (.045) on his fastball nose-dived.

At the same time, Kimbrel's fastball command and velocity improved. The righty averaged 96.8 mph on his heater in August, 97.3 mph in September and finished with a 98.6 mph showing in his final outing against the White Sox.

"He's been absolutely dominant for us," Cubs starter Kyle Hendricks said. "He worked so hard behind the scenes here. It's just awesome to see him going out and being the normal Craig that he is. You can see he's back to having fun, and that's the guy we really need for this team."

Kimbrel was asked recently if he feels like he has something to prove now in the postseason.

"I hope I get my opportunity," he replied. "That's all I can say."