CHICAGO -- Jared Jones didn’t catch much of what Yasmani Grandal was telling him in the sixth inning at Wrigley Field on Thursday night. His fastball wasn’t playing like it normally was, so he was leaning heavily on his slider.

The veteran catcher didn’t like how the pitch was looking in the fifth inning, though. If Jones was going to get through another frame, he needed to locate that breaking pitch.

“He told me to keep it down,” said Jones. “That’s the only thing I could remember. I was pretty blacked out during the game.”

Jones did keep the slider down in the sixth, and to great success. Ian Happ grounded the first slider of the inning to first base, while Michael Busch and Nick Madrigal both went down swinging in a 1-2-3 frame. Jones let out a roar as Madrigal fanned, marking Jones’ seventh strikeout of the game and his sixth quality start in his young Major League career.

With that performance, the Pirates were able to hang on to beat the Cubs at Wrigley Field, 5-4, thanks also in part to homers from Edward Olivares and Nick Gonzales, and a sacrifice fly from Grandal.

While Jones has been perhaps the Pirates’ brightest spot early this season -- pitching to a 2.89 ERA and setting a new high-water mark for Major League pitchers with 155 whiffs through his first nine starts -- keeping the rookie out there in the sixth looked risky. Happ had homered off Jones earlier that night, and Busch doubled before being driven in by Madrigal. With two lefty hitters up for the third time through the order, manager Derek Shelton’s track record suggests that he would normally go to the bullpen.

Not this time.

"Well, I think it's, ‘We trust the kid,’” said Shelton on the decision.

Shelton had faith in his pitcher, and Jones had faith in his slider. In his last start, also against the Cubs, the slider was popping out of his hand early and he lost confidence in the pitch. Even though he would go on to pitch a quality start, Jones looked frustrated talking postgame after that loss last week, saying, “That should never happen, ever. Always being confident with that pitch, that’s key for me.”

So Jones went back to the drawing board. He watched video from his past outings and tried to focus in on what he was doing when it was really good. He was deliberate in bringing that mindset to his midweek catch play.

Mission accomplished. Jones would end up getting all seven of his strikeouts with the slider, as well as all 15 of his whiffs. It marked just the fifth time in the pitch-tracking era (since 2008) that a Pirate pitcher picked up at least 15 swings and misses with their slider.

“I would say it’s back,” Jones said about his confidence in that pitch. “It was gone, but it’s back.”

Grandal doesn’t think Jones lacks confidence on the mound -- it’s hard to blame him when Jones is attacking the zone so efficiently that he didn’t even get to a three-ball count Thursday -- but views an outing like this as just an example where maybe that confidence can build a little bit more. Confidence in himself, confidence in that slider.

“His slider when it's going, it bottoms out,” explained Grandal. “It kind of looks like a fastball. It's pretty hard to hit. When it stays up, it kind of acts like a cutter. It's ‘pick your poison’ to see which one you want to hit.”

Even on a night where the Cubs didn’t whiff on a fastball, they still had to respect the upper-90s heater. Jones was still able to use it as a set-up pitch for the slider, even if saying that out loud took him aback for a moment.

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“Pretty interesting for me to say,” Jones said with a smile. “I’ve never said that one before.”

Jones’ attack plan revolves around that four-seamer and slider. He hasn’t had both pitches clicking the last two times, but still turned in two quality starts. In a way, it is probably beneficial for him to learn how to get Major League hitters out when he doesn’t have that full stuff, Grandal opined.

“There's going to be days when that's going to happen, and we're going to have to revert to that,” Grandal said. “The fact that he was able to do that and work through six was huge."

And if he has confidence in at least one, he can still excel.