Bailey Ober didn't expect to be standing in the middle of Target Field on Tuesday, and it really hadn't sunk in yet when he released his first big-league pitch, a fastball to White Sox shortstop Tim Anderson, to start the game. His attention was suddenly focused when Anderson swung and sent a long fly ball to right.

"I had a lot of bad thoughts going through my head right there," Ober said. "I was just praying it stayed in the ballpark."

It did, barely, and Kyle Garlick caught it on the warning track. But the next batter, Jake Lamb, hit one even farther, a home run that put the White Sox ahead. Then Ober walked Yoan Moncada and gave up a single to Yermin Mercedes, and fell behind 3-1 to Adam Eaton.

Suddenly, his major-league debut looked like it wouldn't last more than 10 minutes. But Ober got Eaton to swing and miss at a fastball up in the strike zone, then foul off another in the heart of the plate. And on 3-2, Ober threw a shoulder-high pitch that should have loaded the bases — but Eaton swung at it, and missed again.

"It was big-time. I needed to get momentum going back to our side," said the 25-year-old rookie, the Twins' 12th-round pick in 2017. "Coming back from that 3-1 count, getting him to strike out, was definitely a sigh of relief."

What did he say to himself on the mound? "All right, I can get these guys out," Ober said. "Let's do this! Let's attack these guys."

And he did for four innings and 82 pitches, surrendering another home run to Yasmani Grandal and an RBI double to Moncada.

"He's a smart guy. He knows what he's doing out there on the mound," Twins manager Rocco Baldelli said of Ober, the College of Charleston's all-time leading winner. "But he also knows as he sees these good major league hitters, he can continue to make adjustments and figure out different ways to approach some of these guys. I thought it was a very promising debut for him."

Totally unexpected, too. Michael Pineda had a cyst removed from his thigh, but the Twins hadn't announced that he would miss his start. So when St. Paul manager Toby Gardenhire called him Monday evening, the Saints' off day, Ober didn't think anything of it.

"He just told me, 'Hey, are you good to pitch tomorrow?' I said, 'Yes sir I am,'" Ober recalled. "He said, 'Good, you're going to the big show.' I was pretty excited. It was a dream come true since I was 5 years old. Really good feelings out there. I was super excited, just really, really grateful to be out there."

He called his parents in North Carolina, and relatives flocked to the Twin Cities on Tuesday, from Connecticut and Arizona and even some who drove from Denver. They all posed for pictures on the field after the Twins' dramatic 5-4 walk-off victory ended.

"I don't know, I'm still waiting for it to hit me. I'm still kind of taking everything in, a little bit of shellshock," Ober said. "Seeing their lineup and facing those guys in the batter's box with everything going on and the crowd, those are the things I'll probably remember."