Antoine Griezmann will be going up against his old club, but his form with the Catalan side is much improved in recent weeks, after missing a number of the aforementioned chances himself early on in the campaign.
"I see Barcelona are in a strong moment," Imanol said in his pre-match press conference, ahead of the two clubs' Wednesday night meeting.
"They may be inconsistent, but that's due to not taking chances.
"In all the matches they play, they are creating enough chances to win.
"I think [Griezmann] is creating a lot, even if he could score more goals.
"Then I think Lionel Messi is still the best player in LaLiga, the one who causes the most disruption.
"Barcelona will be unstoppable as they both hit form."