United play host to Costa Rican visitors Alajuelense at the Robert F Kennedy Memorial Stadium in Washington on Wednesday, a week after the MLS giants were routed 5-2 on the road.
Out of season and out of form with the MLS set to kick-off on March 6, United were put to the sword by Alajuelense, who were inspired by Jose Ortiz's brace at Estadio Alejandro Morera Soto.
Speaking after the opening leg, United coach Ben Olsen said his team took far too long to find their rhythm against Alajuelense, who are on track to advance to the last four in consecutive campaigns.
"We took too long to get into what was a very physical game against a good group. It's pretty simple," said Olsen.
"This was our first real game in a while and it just took us too long [to get up to speed] so we had to spend the rest of the time out there chasing the game.
"Give them a lot of credit - they came at us and gave us a lot of difficulty and we just didn't handle it well.
"I think we did a much better job of handling the game at the end of the first half and into the second half, getting a hold of it, getting up to speed. Just costly mistakes. Very soft goals."
The scenario is far different for fellow MLS outfit Montreal Impact, who entertain Pachuca at Stade Olympique on Tuesday.
Montreal travelled to Mexico and earned a 2-2 draw at Pachuca last week.
A brace from Dilly Duka had the Impact cruising with two priceless away goals eight minutes into the second half before Pachuca hit back through Heriberto Olvera and Ariel Nahuelpan.
While the performance was impressive, Impact centre-back Laurent Ciman rued the two late goals conceded.
"On the second goal, [Evan] Bush and I could have talked to each other," Ciman said. "I think I'm clearing it, he had it in his hands. Alas, we kind of bumped into each other, and the ball falls for the forward [Nahuelpan] who scores.
"I'm complaining a little bit about that, but in no way am I complaining about Bush or one of my team-mates. I just like to win, I'm a winner."
Liga MX Apertura champions America face Deportivo Saprissa on Wednesday with a commanding 3-0 lead up their sleeve.
Costa Rican hosts Saprissa were dismantled in the second half last week as Oribe Peralta ran rampant by scoring two goals in the space of three minutes.
Herediano and Olimpia go head-to-head on Thursday with the last-eight tie locked at 1-1.
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