Darvish said after pitching eight terrific innings in a 5-2 victory over the New York Mets on Tuesday that Kimbrel showed him a knuckle-curveball during a bullpen session this month.
"Kimbrel taught me that pitch, and I feel good," he told reporters. "That's why I used it."
Darvish allowed one earned run on five hits and one walk with seven strikeouts to pick up the win. He said two of those seven punchouts came with his newest weapon.
"He got a couple (batters) to chase, and the curve in the dirt (for the strikeout of Jeff McNeil) was the pitch I wanted after the slow curve," catcher Victor Caratini said.
The 33-year-old Japanese has turned his year around after a sluggish start to the 2019 season. He owned a 4.98 ERA at the end of June, but he has posted a 2.93 ERA across five July starts and a 3.45 ERA in five August outings to drop his overall mark to 4.25.
Kimbrel, who didn't sign until June because of the draft-pick compensation linked to his free-agent status until the 2019 draft, is following a similar upward trajectory. He compiled a 6.75 ERA in July but has a 1.93 ERA in August.
The success of those two pitchers will have a major impact on the Cubs' playoff chances. Chicago is three games behind the NL Central-leading St. Louis Cardinals and currently occupies one of the two wild-card spots.