Jesper Sorensen admitted Vancouver Whitecaps were "second best in everything" as they suffered a 3-1 loss at Chicago Fire.

The Whitecaps struggled to get going in Tuesday's contest at Soldier Field as they tasted a third defeat in six MLS outings.

Mathias Laborda pulled one back for the visitors in the 73rd minute after Jonathan Bamba and Philip Zinckernagel had scored early in each half.

However, Maren Haile-Selassie netted a deserved third for the Fire late on in the rearranged contest, with Sorensen having no complaints.

"I have to be honest and say we were second best in everything we saw on the pitch, which isn't normal for us," he told reporters. 

"I have to look at the structure, because it was not what we wanted. Of course, that's on me. We were not good in the small details or the duels.

"They came out of a lot of 50-50s with the ball. We looked a little heavy and tired."

Vancouver remain top of the Western Conference with 50 points from 27 matches, but the chasing pack are within touching distance.

Sorensen's side registered an expected goals (xG) value of 1.08, compared to 3.91 for their superior opponents.

"Honestly, we didn't play a game where afterwards we can say there are positives to take away from it," Sorensen added.

"All-in-all, we were too far from each other and they were able to create chances like I have not seen in a long, long time."

Chicago have now won back-to-back games and move past Charlotte FC into fourth place in the Eastern Conference with this latest victory.

Bamba's ninth-minute goal was his first since March and set the tone for the hosts, which Zinckernagel added to after missing an earlier penalty.

Laborda then met Oliver Larraz's corner to kill off Vancouver's hopes of a comeback late on.

"It was a strong performance against a very good team," head coach Gregg Berhalter said. "The first half went exactly as planned

"We matched their intensity and even exceeded it for most of the game and deservedly got the lead."

Vancouver were without some key players due to international duty, whereas Chicago welcomed back Robert Lewandowski ahead of schedule.

The Poland striker set up his side's third goal in a reunion with former Bayern Munich teammate Thomas Muller.

Muller took to Instagram after the game to write: "That was a bitter 3-1 loss in the catch-up game against Lewandowski's Chicago."

Chicago are back in home action against New York City FC on Saturday, while Vancouver travel to Los Angeles FC.