When they were knocked out of the US Open Cup last year by Orlando City of the USL PRO, Sporting Kansas City vowed they would come back this year and make a strong run at the trophy they last won in 2012.

Fulfilling that promise will have to wait another year after Kansas City was eliminated by the Portland Timbers, 3-1, in the Round of 16 on Tuesday night at Sporting Park.

“Any time you're in a competition and you get knocked out, it's always disappointing,” manager Peter Vermes sad in his post-match news conference. “Always. It doesn't matter what competition you're in, it's extremely disappointing. It's a trophy that we don't have a chance to win now this year.

"It's not going to sit well all season long. Doesn't matter what happens at the end of the season. You just remember that this is one that we let get away, just because of our lack of defending.”

That lack of defending bothered Vermes most on Tuesday, specifically the ease with which Portland won balls and then did something with them in the other end.

“We made it too easy for their guys on a regular basis. It wasn't as if they were running all over the place,” he said. “We had a lack of organization, we weren't in places that we should have, we weren't aggressive enough to win the ball back.”

Vermes disagreed with the penalty kick whistled against Aurelien Collin, which Will Johnson converted to give Portland a 2-0 lead in the 60th minute, but Vermes also said Kansas City should not have allowed Portland's Steve Zakuani to get that deep so easily in the first place.

“It wasn't a penalty,” he said. “It wasn't, because Collin kicked the ball and then the guy went over his leg after. But I will tell you this: We deserved it, only because we let that same guy dribble around three guys. So at the end, we deserve to give up the penalty.”

Sporting used their eighth different back-line combination of the year on Tuesday, with Seth Sinovic on the left, Collin and 17-year-old Erik Palmer-Brown paired in the middle for the first time, and Kevin Ellis returning to his natural right-back spot thanks to Collin's return from a recurring hamstring strain.

“There's no excuses for that,” Sinovic told reporters. “We've had plenty of experience playing with each other, whether it's practice or on the field. We should be comfortable with each other by now, so that's no excuse.”

Even Soony Saad's 73rd-minute penalty kick – his third goal in as many matches across all competitions – did not provide any comfort to Kansas City on this night.

“I'm not even concerned with the goal thing,” said Saad, who has had to work his way back from a quad injury he aggravated on international duty with Lebanon early this year. “I'm just disappointed that we aren't going to participate in the US Open Cup further this year. We really took pride in that tournament, so it doesn't really matter to me right now.”

Steve Brisendine covers Sporting Kansas City for MLSsoccer.com.