CHICAGO -- It was a vintage fastball from the fingertips of Craig Kimbrel. From Bryan Reynolds' perspective, the pitch probably appeared destined for the heart of the strike zone.

As Reynolds initiated his swing on Thursday in Pittsburgh, the heater began that classic Kimbrel rise. And the fastball kept climbing until it popped into the glove of catcher Willson Contreras, beyond Reynolds' bat and above the top of the strike zone.

"Craig's in a good place," Cubs manager David Ross said recently. "He's on the attack."

That strikeout of Reynolds that sealed Chicago's 4-2 victory also marked the 350th save of Kimbrel's career. Names like Randy Myers, Rollie Fingers and John Wetteland are in his rear-view mirror. The likes of Troy Percival (358), Jeff Reardon (367) and Jonathan Papelbon (368) are next in Kimbrel's sights.

Reaching that milestone was more of an inevitability than a surprise for Kimbrel, but the veteran closer's meteoric ascent up the all-time saves chart was slowed in recent years.

Right now, following two turbulent tours with the Cubs -- seasons with obstacles both in and out of Kimbrel's control -- the right-hander is looking like himself once again. He has struck out nine of the 14 batters he has faced, with no hits allowed through four outings.

"Players and baserunners are telling me that he's back on point," shortstop Javier Báez said. "Seeing the way he's pitching to other guys and seeing the ball, the movement, the way he wants, it's obviously great."

That pitch movement is crucial to Kimbrel's success.

When Kimbrel is at his best, his fastball has that seemingly physics-defying rise and checks in at 96-98 mph on the radar gun. Both are happening right now. When Kimbrel is right, he is able to wield his devastating curve both for called strikes and chase swings. That is happening right now, too.

The same could not be said early in 2020, when Kimbrel was a mess mechanically in a season in which every win carried much weight. It was the same throughout ‘19, when he went unsigned until June and then dealt with injuries.

"It was definitely tough times," Kimbrel said.

Early in 2020, Kimbrel's fastball had more run than rise, leading to more barreled balls. The ineffectiveness of that pitch played into inconsistency with the breaking ball. Kimbrel gave up seven runs and walked five in his first four games of '20 and was removed from the closer's role.

Behind the scenes, Kimbrel got his delivery issues ironed out, improving his direction to the plate and avoiding becoming too rotational. And dating back to Aug. 14 of last season -- his first shutout inning last year -- Kimbrel has been one of baseball's elite performers.

"I don't know if there's any big turning point," Ross said. "I think he had a really good season last year outside of a couple outings. The body of work, total last year, was really good after he identified some things."

Dating back to that Aug. 14 appearance, Kimbrel has spun a 1.04 ERA with 35 strikeouts and seven walks in 17 1/3 innings (63 batters faced). His 55.6 percent strikeout rate in that span is first among pitchers with at least 10 innings.

Since the start of September last year, Kimbrel has allowed no runs and just three hits in 12 innings, in which he has struck out 22 of 38 batters faced with zero walks.

Kimbrel did allowed nine runs in his first three Cactus League outings this spring, raising some red flags given the past issues. Then, he quickly made the needed fixes -- based on the adjustments learned last year -- and ended with four straight scoreless showings.

Cubs pitching coach Tommy Hottovy said a big change from Kimbrel has been learning how to utilize the Rapsodo and Trackman data to get back on track. The veteran even had a data-tracking setup at his home for offseason training.

"Last year, as crazy as it was," Hottovy said this spring, "guys learned a lot about themselves. And when you go through what Craig went through last year, you learn more so than anything, like, 'OK, when I'm right, this is what the data says.'"

At the moment, the data says Kimbrel is right where he needs to be for the Cubs.

Per Statcast, Kimbrel’s fastball has checked in at 96.6 mph this month. The last April readings for Kimbrel were in 2018, when he averaged 96 mph in the first month en route to 98-plus by season's end. Kimbrel was over 98 mph by the end of last season, too.

And right now, Ross -- once Kimbrel's catcher during their days as teammates with Atlanta -- has a deep trust in the closer once again.

After Dan Winkler walked the bases loaded with one out in the eighth on Thursday, Ross summoned Kimbrel from the bullpen. The fact that Kimbrel pitched on Wednesday gave Ross brief pause, but the closer had only thrown a dozen pitches.

"I was definitely on the fence," Ross said. "But we had a good conversation."

Kimbrel answered the bell with two strikeouts to escape the eighth. He used a back-foot curve to entice a swing from Dustin Fowler, and then got Wilmer Difo to chase a heater that rose high and outside. Kimbrel then set down the side in order in the ninth.

That marked the first regular-season five-out save of Kimbrel's decorated career.

"Let's take a moment to appreciate just the greatness of Craig Kimbrel," Cubs veteran pitcher Jake Arrieta said. "He's a special one and we're fortunate to have him. He's going to climb the ranks, especially with the stuff that he still has.

"He might end up being No. 1 at the end of the day."

Hall of Famer Mariano Rivera holds that distinction with 652 career saves.

Kimbrel smiled when told of Arrieta's prediction.

"Let's focus on 351 and then go from there," Kimbrel said.