HOUSTON >> In the minutes after the Twins were walked off by the Houston Astros, Willi Castro was still trying to piece together what, exactly, had happened. Astros second baseman Mauricio Dubón hit a ball to Castro in left that he leapt for it looked like it hit his glove before rattling off the wall.

But with a quirky outfield design at the ballpark, it was hard to tell.

“I saw it,” Castro said of the ball, which went for the game-winning hit in the Twins 2-1 loss to the Astros on Sunday afternoon at Daikin Park. “I don’t know what happened there. I think I should have caught that ball. It got right in that corner there. … I don’t know if I hit the wall before I jumped or if I jumped before, but yeah, I should have caught that ball.”

But with the way things have gone for the Twins (36-35) of late, they still might have lost even if Castro had caught it. The loss, which came in the 10th inning after Jhoan Duran had allowed the game-tying run to score in the ninth inning, capped off a series sweep for the Astros (41-30).

And it came on a day in which the Twins had opportunity after opportunity but could not capitalize, finishing 0 for 8 with runners in scoring position and leaving eight men on.“It kind of feels like we’re swimming upstream a little bit right now,” manager Rocco Baldelli said. “Nothing’s coming too easily for us but you have to find a way to piece something together and make it work even when it’s not going cleanly and you’re not feeling great and all of those things.”

The Twins had been leading for nearly the whole game when Brooks Lee, who now has Major League Baseball’s longest hitting streak at 15 games, sent a pitch from starter Brandon Walter out to left field in the third inning.

The Twins scored six runs in the series, all of which scored via the longball as they struggled to push runs across.

“Somehow I just keep putting together good at-bats from both sides of the plate. Got to keep it going,” Lee, who had three hits on Sunday, said. “Hopefully a couple of guys get going and we just try to win some games. That’s most important.”

And for much of Sunday, it looked like they would.

Pitching in his hometown in front of a cheering section of around 30 friends and family members, starter Simeon Woods Richardson was stellar, beginning his outing by retiring the first 13 batters he faced.

The first and only hit he gave up came in the fifth inning. His only walk of the day followed that, but he locked in and retired the next two batters in order to end the Astros’ threat.

“He threw a ton of strikes,” Baldelli said. “I mean they were coming out of their shoes trying to swing at every strike they saw. He got a lot of weak contact.”

After just 53 pitches, with a rested bullpen, an off day on Monday and a slim one-run advantage, Baldelli then turned it over to the bullpen, getting a combined three scoreless innings from Brock Stewart, who struck out two of three batters he faced, and Louie Varland, who threw two innings for the first time this season.

But in the ninth, Duran walked the first batter he faced, Jeremy Peña, and he wound up coming to score on a Victor Caratini sacrifice fly. And after the Twins could not advance their automatic runner past second base in the top of the 10th against all-star closer Josh Hader, Dubón ended it in the bottom of the inning.

“We’ve got to find a way to get three outs at the end of the game,” Baldelli said. “Pretty simple but we also have to help ourselves a little bit more, too.”