In its deepest, darkest days those first two seasons, Minnesota United coach Adrian Heath insisted no conclusions be made about his club until after its third MLS season.

Still at least two months from season's conclusion, the Loons on Wednesday celebrated both their biggest player signing yet and a 2-1 U.S. Open Cup semifinal victory over Portland that sends them later this month to Atlanta to play their first final, in that third season.

A small section of Allianz Field fans held up images of 18-year-old Uruguayan prospect Thomas Chacon on a stick when the team announced his signing with a video montage at halftime on the big board above the standing-only Wonderwall.

Not long after, young striker Mason Toye's 64th-minute goal — the second half's only one — stood to be his second game-winning Open Cup goal in four such games this season.

United now is undefeated in its past 11 MLS and Open Cup games (9-0-2), dating to a June 8 loss at Colorado.

Afterward, those singing, chanting fans on that Wonderwall didn't want to go home. Neither, it seemed, did veteran defenders Michael Boxall and Ike Opara, who saluted the anounced crowd of 15,073 with their jerseys flung off while Heath waved his hands over his heads in the gathering blue smoke.

"It's a great day for the club," Heath said. "We've gone to our first final. We've added a Young DP [Designated Player] that we paid a lot of money for, a kid we think is going to be outstanding for the future. So things are good. But guess what? When I look back in my career, I know I didn't like when we got beat in the final. So it's great tonight, but we hit it again in the morning."

Wednesday night, they danced. Both to the sing-song music of Oasis in front of the Wonderwall and in the locker room, where Toye and rookie Chase Gasper offered their homage to NBA superstar Kevin Durant's pregame dance routine.

"We were just kind of imitating him," Toye said.

United beat Portland for the second time in three days, in the same stadium. Sunday's last-chance victory on Ethan Finlay's penalty kick in second-half stoppage time brought them three points in MLS standings and second place in the rugged Western Conference.

Video (01:45) Loons sporting director Manny Lagos and coach Adrian Heath discuss Wednesday's signing of 18-year-old Uruguayan midfielder Thomas Chacón.

"It's a little weird," United veteran midfielder Ozzie Alonso said about playing a rival team he faced often when he played a decade in Seattle. "But I'm happy to beat Portland twice in three days to get to the final."

Wednesday's victory gives the team the opportunity Aug. 27 to win a tournament within an MLS season for which both American amateurs and professionals have competed to qualify since last fall.

To do so, United must beat an Atlanta team that entered the league the same as it did in 2017 and spent tens of millions on young star players who won the MLS Cup last season. Meanwhile, United allowed 141 goals in its first two seasons and didn't sniff the playoffs either year.

All the while, Heath said wait until that third season — until new Allianz Field opens, until the roster is properly fortified.

"I know how far we've come," he said. "I know how hard we've worked to get to where we are, second in the West. You know how tough the West is, and now we've reached a final as well. You can dress it whichever way you want, but we've haven't spent what everybody else has spent. We didn't have a DP for 18 months. But we got better when we could, when it was the appropriate time.

"If we continue to do it, we're going to be fine."