PITTSBURGH — Paul Skenes tugged on one black dress shoe, then another. He slowly unfurled his 6-foot-6 frame from the chair in front of his locker, pulled on a blue blazer, ran his hands through his black hair, and turned to face the cameras.

It’s not just the 21-year-old’s stuff that’s different.

While most of his Pittsburgh Pirates teammates quietly exited the clubhouse in T-shirts, shorts and sneakers following a 7-6 loss to San Francisco on Thursday, Skenes looked as though he was heading out for a business dinner.

Fitting for a player who takes his dream job very, very seriously.

There is a maturity to Skenes both on and off the mound that belies his age. Both were on full display in his third big league start, when Skenes didn’t so much dominate the Giants for six innings as much as he out-thought them.

On a day when command of his breaking balls was iffy at best and he “only” threw four pitches that reached 100 mph and struck out just three of the 23 batters he faced, Skenes found a way to make it work anyway.

“Just have to make pitches because they’re going to put the ball in play,” Skenes said. “Just got to trust my stuff and trust that it’s going to (create) weak contact. Overall, pretty good.”

Six days after Skenes threw six electrifying no-hit innings against the Cubs, the Giants managed to ding him for six singles and a walk. They also hit into a pair of double plays and managed just one run despite getting at least one baserunner in every inning but the second.

And maybe that is as important in Skenes’ development as what he showcased against the Cubs. He’s not going to have his best every time out. No pitcher does. Yet he gave the Pirates a chance to win anyway in the kind of performance that may end up speeding up a learning curve that’s already way ahead of schedule.

“There’s going to be so many growing moments for him, but last start out he doesn’t give up any hits,” Pittsburgh manager Derek Shelton said. “Then this start he has to navigate through traffic, he has to navigate through some veteran hitters. It’s definitely going to make him better.”

San Francisco third baseman Matt Chapman — like Skenes a graduate of El Toro High School in Lake Forest, California — doesn’t think it’s a coincidence that the Giants made their comeback only after Skenes exited.

“I think the future’s bright for that guy,” Chapman said. “And it’s exciting to see somebody from the same high school go out there and have success as quickly as he has.”

The window to win in Pittsburgh is creaking open. Skenes is proving he’s more than capable of helping with the lifting.