The Portuguese boss kept his promise by donning a hat and maskafter leading his sideto the Champions League knockout stages
Shakhtar pulled off a memorable 2-1 victory over Manchester City on Wednesday night which ended the Premier League side's 28-game unbeaten streak.
Diminutive Brazilian Bernard curled in a beauty in the first half, shortly before Ismaily made it 2-0. Sergio Aguero pulled a goal back for the visitors – already group winners pre-match – with a penalty in added time, but it wasn't enough as Shakhtar finished the group stage in second place.
The Ukrainian side's Portuguese manager Fonseca had promised to dress up as Zorro if he got his team to the last 16 - and so he did.
"This is the most joyful news conference of my career," Fonseca chuckled to baffled reporters.
"I feel great joy. I think not only Shakhtar's supporters but all Ukrainians have to be proud of our team."
Shakhtar faced a tough task making it out of the group ahead of Serie A high-fliers Napoli, whose 2-1 loss to Feyenoord capped a miserable night for the Italians.
Fonseca's side are still playing away from Donetsk amid political troubles, 154 miles away in Kharkiv as the crow flies.