PORTLAND, Ore. – Minnesota United will have to postpone celebrating its first trip to Major League Soccer's postseason.

The Loons had a chance to secure that historic bid with a win Sunday but instead played the Portland Timbers to a scoreless draw. United (14-10-7) failed to win in Portland for the third time in three tries since joining MLS in 2017.

Minnesota United coach Adrian Heath chose the optimistic point of view after the team's first Portland point.

"We would have taken this situation before the season started," said Heath, whose team remains in third place in the MLS West standings. "Our goal was to make the playoffs."

United's next chance to clinch a playoff spot will come Wednesday, when the Loons host Sporting Kansas City at Allianz Field.

The Loons managed to tie the Timbers (13-13-5) largely because of Vito Mannone's performance in goal. The keeper faced 29 shots but made 12 saves and posted his 11th shutout of the season.

"Any time I get a clean sheet, we create a chance for ourselves — we can win games," Mannone said. "Unfortunately, we didn't get the three points [awarded for a win], but against a team like Portland, which plays with a lot of intensity and takes cross after shot after cross, you really have to be on top of your game."

The Loons had trouble generating scoring chances, finishing with four shots on goal. Forward Mason Toye had three of those, two in the first eight minutes.

"We turned the ball over too cheaply at times and then, on the reverse side, I thought that if we would have played with the quality I know we possess, we could have won the game," Heath said.

"We had too many really good opportunities, and we didn't really come back with the final ball or the really decisive pass."

The Loons put pressure on the Timbers in the 62nd minute, but Robin Lod headed Darwin Quintero's free kick off the crossbar. In the 86th minute, midfielder Ethan Finlay's shot from outside the box sailed over the net.

United's best chance to score — and win — came in second-half stoppage time, when Timbers' Diego Chara badly misplayed the ball in transition and keeper Steve Clark stopped Kevin Molino one-on-one just inside the 18-yard penalty box.

"I know people will probably talk about Kevin's chance at the end," Heath said. "… I think it might have been unjust for them because they certainly had done enough to maybe won the game today."

Mannone endured a high-pressure attack in the first half. He made a diving stop in the eighth minute, a leaping grab in the 17th and a kick save in the 40th.

"When they have the ball, they can spring out," Mannone said. "They have a good counterattack, and if you're not ready for it, sooner or later, you're going to be facing a shot — especially if you keep losing the ball like we did."

United defender Ike Opara left the game at halftime because he felt ill.

"He just didn't feel well at all," Heath said. "Struggling concentrating, you can't carry players in a place like this."

It wasn't clear whether Opara would miss Wednesday's game. "We're hoping not," Heath said. "We're hoping he'll be fine."

Striker Angelo Rodriguez and newcomer Thomas Chacon again were left out of the 18 selected as starters or subs.