Man United are the firm favourites to make the final in Stockholm after recording a 1-0 victory in the first leg of their last-four clash away to Celta on Thursday night.
Aspas has scored 24 times in all competitions for Celta this season, but the 29-year-old struggled to make an impact against a stern Man United defence.
Berizzo has said that his side are still in the semi-final, although the Argentine concedes that their chances rest firmly on Aspas's ability to influence the reverse game next week.
"I think Aspas was very closely marked throughout the match. Due to being heavily marked he wasn't able to get free and we will work hard to find a solution so that Old Trafford he can have more of an impact," Berizzo told reporters.
"Really, we hope we can work to fix that as this is not the end, I will repeat myself. Our home matches show us, technically and tactically, what we need to do to get through in the away games."
Celta Vigo will return to La Liga action this weekend with a trip to Malaga.