CHICAGO -- Before Duke Ellis made his Major League debut in the ninth inning of the Cubs' 7-6 victory over his White Sox on Tuesday at Wrigley Field, he shared his secret for being such a good basestealer.

“No fear of getting thrown out or picked off,” Ellis said. “If you have any fear or doubt, then automatically you’ll get thrown out. Go get it with confidence and whatever happens, happens.”

Whatever happened for Ellis on Tuesday was the good and the bad of an exciting Crosstown Cup showdown. After pinch-hitter Oscar Colás fought back from a 1-2 count against Héctor Neris to draw an eight-pitch, one-out walk in the ninth, Ellis entered as a pinch-runner and promptly swiped second.

That effort is why the White Sox (15-46) added Ellis, after the 26-year-old picked up 34 stolen bases in 35 attempts for Double-A Birmingham this season. Ellis was sent out in the ninth to steal third, as well, with the White Sox trailing by one. After successfully nabbing second, he had a good jump on the next pitch from Neris to Corey Julks before pulling back on the attempt.

Neris and Nico Hoerner caught him two pitches later on a 1-2 count with a back pick at second, as Ellis was picked off for the second out of the inning. It’s a learning experience for the rookie coming as part of the White Sox 12-game losing streak.

“Got a little too aggressive and the back pick got me,” said Ellis, who handled the postgame interview session like a veteran before going to share the debut with his family back on the field. “It was a big learning experience for me. For the next time I’m in that situation, trust the instincts and go on the first jump. Then we don’t have to worry about it.”

“He was looking to take third in that situation, to be on third with one out,” Cubs left fielder Ian Happ said. “And that's a completely different ballgame. So to get that out there, massive. Great job."

Ellis wasn’t the only young White Sox player to take something away from Tuesday’s setback.

Lenyn Sosa launched a two-run home run off Cubs starter Shota Imanaga to cap off a five-run fourth and give the White Sox a 5-0 lead. Sosa had two hits and lined out hard to left to open the ninth.

Jordan Leasure (0-1), who has been pitching effectively in high-leverage situations for much of his rookie campaign, entered in the eighth with a 6-5 White Sox lead. The right-hander walked Cody Bellinger on four pitches with one out, and Christopher Morel reached on an infield single when shortstop Paul DeJong’s diving attempt resulted in a glove flip to Danny Mendick that was too high to nab Bellinger at second.

On a 1-0 pitch to Happ, the switch-hitter ripped a double to right to drive in two for the go-ahead runs.

“Just knowing in that situation trying to lock in a little better, make a better pitch, especially to those caliber of hitters,” Leasure said. “Overall it felt great, stuff felt great. Just falling behind hitters. That was the difference.

“I threw not a good pitch to Happ and he’s a really good hitter, so he got me. Not much I can do from that looking back.”

This short series finishes Wednesday night, and Ellis will be right back out there for the White Sox if the situation dictates. He’ll have that same speed, that same fearless approach, but maybe with a little more knowledge from a big-game situation.

“Oh, it was exciting,” Ellis said. “It was honestly a dream come true and that was the situation I wanted to be in. I’m glad they trust me to be in that situation and hopefully there will be a lot more to come. All I can do is learn from it and be better for the next one.”

“He’s going to be good here for a long, long time. And he’s going to learn from this. He’s a student of the game,” White Sox manager Pedro Grifol said. “He was put there to do exactly what he did, and he got picked off. It’s not a big deal. That’s not what won us or lost us the game. This one got away.”