Juan Martin del Potro produced a truly sensational fightback to beat Marin Cilic in an epic encounter and set up a decisive fifth rubber in the Davis Cup final.

Having moved 2-1 up in the tie with victory in Saturday's doubles, Croatia looked set to earn their second Davis Cup title when world number six Cilic took the first two sets at Arena Zagreb.

However, Del Potro - who has been involved in a host of absorbing contests on his return to full fitness in 2016 - refused to give up and delighted the raucous contingent of visiting Argentinian fans by recovering to prevail 6-7 (4-7) 2-6 7-5 6-4 6-3.

Del Potro's magnificent victory, which took four hours and 53 minutes, means the winner of the competition will be decided by the final singles match between Ivo Karlovic and Federico Delbonis.

Argentina are seeking a first title, having been runners-up on four occasions, while Croatia's only previous success came in 2005.