FOXBOROUGH, Mass. – The Chicago Fire saw the US Open Cup as a way to salvage an otherwise disappointing season, one in which they’ve sputtered to the worst record in MLS with about a third of the campaign remaining.

But those hopes melted into frustration and defeat at Gillette Stadium on Tuesday, as their run terminated in the semifinals with a 3-1 defeat to New England. The finish was marred when star forward David Accam was shown a straight red after his hard tackle on the Revs’ Kelyn Rowe instigated a scrum near midfield.

“We were losing and I tried to win the ball, and I pushed a little too hard and I made a silly mistake,” Accam said postgame. “The guys showed a lot of passion, but today we were not good enough. We need to learn how to start games earlier. We sat back, and they put pressure on us and dictated the game.”

Chicago conceded a 16th-minute goal on a Kei Kamara PK after Rodrigo Ramos was whistled for a foul on Rowe near the edge of the box. New England continued to dominate the run of play for much of the half, but Chicago’s fortunes seemed to shift right before halftime when Accam collected a pass from Michael de Leeuw in the box, faked out defender Je-Vaughn Watson and beat keeper Brad Knighton to the near post to tie the score.

But the Fire gave back the advantage less than two minutes later on a goal off a corner kick, and never truly threatened in the second half.

“We still have the issue that once we concede a goal, we start to play the way we want to play. We feel a relief of having the negative result, so now it’s actually when we react. We want to be the team that … imposes his style,” said Chicago coach Veljko Paunovic.

“I’m really proud of our guys. I think our team made a huge effort and, as I said, this is the best we can do at this point and we learn from everything.”

With their Cup run now over, the Fire will turn their attention to using the final stretch of MLS regular-season games to improve physically and mature mentally for next season.

“We have to grow up in this league and this competition just doesn’t give you too much time for that. You have to react in the next game and I think the pace of the competition and the pace of how well we grow, it’s not the same pace,” Paunovic said. “I think we are behind, but that’s the part of the process.”