ST. PETERSBURG -- Mitch Keller was teetering just one inning into his start Friday night against the Rays. 

Victimized by weak contact and worn down by long at-bats from Tampa Bay hitters during a three-run second, Keller was clearly frustrated. 

If his balk that allowed the third run to score wasn’t enough of an indication of his irritation, his expletive that echoed throughout Tropicana Field as he made his way off the mound at the inning’s end certainly was.

But the 26-year-old, who has pitched so well since being reinserted in the Pirates’ rotation at the end of May, steadied himself and tossed three scoreless frames that allowed his team to fight back and tie the game in the fifth before falling, 4-3, in 10 innings.

The Pirates had a golden opportunity to notch their second consecutive extra-inning victory with runners on the corners and no out, but strikeouts from Jack Suwinski and Michael Chavis bookended a Bryan Reynolds popout. Rays pinch-hitter Harold Ramírez made the Bucs pay in the bottom of the inning with a one-out single that scored Vidal Bruján from third.

“We put ourselves with a chance to win the game in the 10th and just didn’t come through,” manager Derek Shelton said.

Early on, it looked like this game would never reach the 10th as Keller labored through that 37-pitch second inning.

The Rays’ three runs came on a 79 mph seeing-eye single from Luke Raley, an 0-2 curveball below the strike zone that Jonathan Aranda smacked through the right side for his first MLB hit, and that balk, which Keller said was just a “brain fart” and the most frustrating part of the inning.

Said Shelton: “With him throwing the sinker, he’s going to give up ground-ball base hits. So, really can’t fault him for that. He continued to battle and gave us five. … He did a nice job bouncing back after that tough inning.”

It’s an inning that Keller said might have affected him more in the past. He acknowledged that his ability to battle beyond that frame is a sign of growth.

“I think, in the past, it might have snowballed on me and affected the rest of the game. Just being able to slow the game down and analyze what’s going on -- it’s not as bad as I think it is -- and just keep pushing forward.”

Over his past five starts, Keller has posted a 2.96 ERA through 27 1/3 innings, with a ground-ball rate north of 50 percent in all but one of those outings. Another good sign for the sinkerballer Friday was that all but three of his 15 outs were either a strikeout or a groundout.

As Keller settled in, the Pirates’ bats started coming alive. After a few innings without much hard contact, Chavis got Pittsburgh on the board in the fourth by demolishing a changeup for his eighth home run of the year and his second in as many games. Diego Castillo followed two batters later by bashing another changeup 411 feet to left field. Hoy Park then ambushed Rays starter Jeffrey Springs to open the fifth inning, sending an elevated 90 mph fastball into the seats in right-center.

Chavis, one of the few Pirates who have played at Tropicana Field before, has hit three home runs in 30 at-bats under the dome. It’s a stadium that will always have special significance for him.

“I feel comfortable playing here,” he said. “Maybe it’s because I made my debut here [with the Red Sox in 2019], and it just reminds me of that."

He wasn’t the only member of the Pirates to make a homecoming of sorts Friday. Shelton was the Rays’ hitting coach from 2010-16. His first game as a manager was supposed to be in this stadium with the Pirates in 2020, but it was wiped out by the COVID-19 pandemic.

Despite the two-year delay, Shelton said before the game that it felt good to be back.

“It’s kind of like home," he added. "I was here for seven years. It would have been really special for the first game that I manage to be in this building just because there are so many friends here and because I still live here with my family. But it’s cool to be back. It’s cool to see a lot of people.”