BOSTON -- Sunday was not just another strong start for the blistering-hot Nick Pivetta. It was also a microcosm of his season.

When Pivetta walked four of the first 10 St. Louis hitters he faced, you wondered if his run of tremendous performances dating back to May 7 was finally going to end.

Instead, Pivetta quickly adjusted and didn’t walk anyone for the rest of the day. Backed by pinpoint fastball location and a knuckle curve that had the Cardinals buckling, Pivetta pitched the Red Sox to a 6-4 win Sunday at Fenway Park in the rubber match of a three-game series.

“I think I was a little jittery today [early], was getting ahead of myself a lot. Arm was kind of lagging behind. A lot of misses up and away and then down and in,” said Pivetta. “Then I got my legs underneath me a lot. It was better after that and just kind of went from there.”

The way Pivetta is able to make quick adjustments now -- be it in-game or from start to start -- explains why he is finally reaching the potential he was tagged with for so long.

“Yeah, I think I’m getting much better,” Pivetta said. “Me and [pitching coach Dave Bush] talked after the game. I don’t know if I make that adjustment last year so I just think it’s kind of the work that I put in, kind of the rhythm that I’m in that I’m able to make that adjustment there.”

When Pivetta started his season 0-4 with a 7.84 ERA in his first five starts, there was a lot of adjusting to do.

After brainstorming with Bush, quality control coach Jason Varitek, manager Alex Cora and other staff members, Pivetta not only got off the mat but has turned into the best version of himself at 29 years old.

In a nine-start run beginning May 7, Pivetta is 7-1 with a 1.77 ERA. During that stretch, Pivetta has gone six innings or more eight times, seven innings or more five times and eight innings or more twice.

Starts like this latest one against the Cards -- seven innings, four hits, 10 strikeouts -- are becoming the norm.

When the top of the seventh inning started Sunday, Cora had two relievers warming up. Almost as if he was sending a message to his manager that such an insurance measure wasn’t necessary, Pivetta fanned three batters in succession to end his 108-pitch day.

As he walked off the mound to the roars of a packed house of 35,989 at Fenway, Pivetta aggressively pumped his right fist as he got close to the dugout.

The Red Sox are feeding off the energy and consistency of the righty who is standing in as the ace at a time Chris Sale and Nathan Eovaldi are both on the injured list.

“He’s an electric kid all the time,” Boston catcher Christian Vázquez said. “And you guys saw it in the playoffs last year.”

Vázquez said that after the laborious stretch to open Sunday’s game, his battery mate got back to being “normal Pivetta.”

At any previous point in his career, it would have been hard to know what that meant given the inconsistency that trailed Pivetta.

Now, the Red Sox know what “normal Pivetta” means, and they are loving it. What is Vázquez’s definition?

“When he attacks the zone with his fastball no matter who’s hitting,” Vázquez said. “He’s got a great fastball. If he throws 91 or 96, his fastball is playing all the time, and he’s got a good curveball so we can survive with that.”

Thriving more than surviving, Pivetta’s in-season turnaround mirrors Boston as a whole.

The team that started the season 11-20 is 9-1-2 in the past 12 series. This, after starting the season 1-7-1 in series play.

The Sox are 13-4 in June, outscoring the opposition 82-51 over that span. They are 26-12 since May 10.

“Yeah, it was a really big series for us personally,” Pivetta said. “They’re a tremendous baseball club. And to bounce back from that [11-2 loss Saturday] night as well that got away from us, I think it just kind of sets in stone what type of baseball team we are, how much hard work we’re putting in as well and how good our guys are kind of running right now.”

Without question, Pivetta has been one of the top pace-setters for his rejuvenated club.