The Argentine winger signed a four-year contract with Kharkiv today, ending a three-year spell in Serie A with Catania.
He told the club's official website: "I am very happy, I want to thank the leadership of Metalist.
"I have had offers from Inter, Fiorentina and Atletico Madrid. But Metalist was the most persistent and won the fight for me, so here I am.
"I have a great desire to start training with the team and meet the head coach [Myron Markevych]. And, of course, the Champions League. Everyone wants to play in this tournament."
The 25-year-old becomes the seventh Argentine to join last year's runners-up in the Ukrainian top flight, as they attempt to earn Champions League qualification for the first time.