"We're frustrated we're not in this competition any more, but we have to regroup and we have to focus on the league," the United States forward said.
"We have to make sure we finish in fourth place and make sure we're in the Champions League next year.
"That's the only thing we can do to salvage this season and say we had a good year. That's been the goal for the season.
"It's important that we get into the Champions League."