The Twins bade farewell this season to the first-place Chicago White Sox with Wednesday's 1-0 victory that won consecutive series over American League division leaders, with a third coming to Target Field on Friday.

They won their 50th game this season — 17 fewer than Chicago — with rookie starting pitcher Bailey Ober working into the sixth inning against a White Sox team he now has faced five times in 13 career starts.

Sizzling second baseman Jorge Polanco provided a warm summer afternoon's only run with a sixth-inning homer struck into the bullpen before an audience announced at 22,370.

Four days after they won three of four games at West-leading Houston, the Twins followed Monday's 11-1, series-opening drubbing with victories 4-3 on Tuesday and Wednesday's shutout that included scoreless work by relievers Caleb Thielbar, Juan Minaya and Alexander Colome as well.

Together, they limited Chicago to six hits — all off Ober — while the Twins had just four.

It's a bullpen remade by trade-deadline deals and Taylor Rogers' finger injury.

"We had to be almost perfect today to win the game," Twins manager Rocco Baldelli said, "and we were."

East-leading Tampa Bay arrives Friday for a three-game series during the season's longest homestand.

On Wednesday, Ober unveiled a reworked slider to which he made a "couple tweaks" since his five-inning outing on Friday against the Astros. He wanted to throw it a little harder, disguising it as a fastball until it bit batters at the end. Then when hitters looked for that new slider, he beat them with a high fastball on a day he threw 82 pitches, including 54 strikes.

"It felt great, felt really good spinning out of my hand," said Ober, the 6-9 right-hander whom the Twins drafted in 12th round in 2017. "I need to get a little bit more consistent, but I was happy where the velo(city) was."

Ober walked one and struck out six, including designated hitter Jose Abreu twice and first baseman Andrew Vaughn three of four at-bats. One time, Vaughn stirred up dust when he slammed his bat into the batter's box afterward.

BOXSCORE: Twins 1, White Sox 0

Baldelli called Ober's familiarity with the White Sox so often, so early "kind of odd," but a necessary part of a young pitcher's development, whenever it comes.

"Especially early on in guys' career, that does become a thing," Baldelli said. "It's a real part of the game when you start facing teams, especially good teams a lot. … This is part of baseball. To get to the next small step in your career, you have to find a way to get the same hitters out over and over again.

"Is it easy when you're facing really talented guys on the other side? No, nothing is easy in this game."

Ober's 5⅓ innings pitched matched a career high. He faced the first two batters in the sixth, then left when Thielbar entered to get the final two outs.

At inning's bottom, Polanco stepped up with one out and hit the first pitch from Jose Ruiz over the left-center field fence, four days after he hit his career-first opposite-field homer in Houston.

"Fastball, first-pitch fastball," he said. "And I put a good swing on it."

His eighth-inning triple hit high off the right field wall, not far from becoming a second homer and a 2-0 lead. Polanco is only the second Twin – Ryan Jeffers the other – to homer and triple in a game this season. He has hit seven homers with 13 RBI in his past 14 games.

"He's driving the ball well," Baldelli said. "He's not trying to do too much. He's just trying to use the whole field and he's kind of locked in right now. When you've got a guy with that kind of ability who's really feeling it, he's just driving the ball where it is pitched and those balls are leaving the yard right now."