Higuain has fully recovered from a back op that he underwent in January.
"It's a great pleasure to be in the (Champions League) quarter-finals with this team - more so after the injury I had where I didn't know when I would be able to return," he said.
"To be back at this stage and be able to help the team is very important.
"Many people said I wouldn't return this season. I heard many opinions. I tried to recover as soon as possible in order to return before the end of the season. Thanks to God I'm here.
"It proved that statistics aren't everything. I'm ready to help the team and I will have to take it step by step as I get back to form."