MESA, Ariz. -- On the same ball field that the Cubs call home for about five weeks each year during Spring Training, right-hander Keegan Thompson donned an AFL uniform Saturday afternoon, but he looked like a big leaguer.

Thompson was masterful in Mesa’s 5-1 win over Peoria, as he tossed five scoreless innings while yielding one hit -- a triple to lead off the fourth that he eventually worked around and capped off by nabbing a runner attempting to steal home.

After recording at least one walk in each of his first five starts with the Solar Sox, Thompson issued zero free passes against the Javelinas. In fact, he peppered the strike zone, tossing 45 of his 54 pitches for strikes. And it what was one pitch in particular that spurred his success.

“The changeup,” Thompson said. “I changed the grip and just threw it today instead of trying to make it do too much.”

Injuries put a wrench in Thompson’s plans during the 2019 regular season, limiting him to two starts with the Cubs’ Rookie-level affiliate in the Arizona League and one start (April 6) with Double-A Tennessee. That, too, was a five-inning performance with no runs allowed.

After kicking off Fall League play with an electric three-inning showing with no hits yielded and five strikeouts, Thompson hit a snag. He pitched to an 8.78 ERA in his last four starts entering Saturday, but those troubles were nowhere to be found against the Javelinas.

When asked about how his plan of attack was different this time around, Thompson summed it up succinctly: “Just locate and try to get some guys out and not give up the hits and runs that I have been giving up.”

There was another Cub doing damage Saturday as well. Jared Young had gone his first 35 Fall League at-bats without going deep before he dug in to face Forrest Whitley, the Astros’ No. 1 prospect per MLB Pipeline and No. 16 in MLB, for the second time. But with Whitley supplying plenty of the power, Young laced a solo shot to right-center field.

Whitley, who entered the day with a 1.13 ERA through four starts, had typically made quick work of opposing batters. The home runs that he allowed -- one to Young, the other to Angels top prospect Jo Adell (MLB No. 5) -- were the first that he surrendered during his time in the Fall League. His start unraveled a bit in his final frame, but he finished with three runs allowed on five hits and two walks to go along with four strikeouts over five innings.

In short, Thompson, who made just a single Double-A start in 2019, outdueled one of the game’s premier pitching prospects.

Working against some of the best is nothing new for Thompson, who starred at Auburn for three seasons and posted a 2.46 ERA over 41 college appearances. That much is evident by his success on Saturday.

How quickly he ascends up the ranks only time will tell, but he's closing 2019 with a tantalizing vision of his potential.