4. London Olympics, 2012 - Federer d. del Potro, 3-6, 7-6(5), 19-17
A match which proved that best-of-three sets can still provide extraordinary, extended, emotional epics, Wimbledon was the setting as Federer and del Potro competed to reach the final of the London 2012 Olympics, with the winner guaranteed a medal.
Federer was hunting for the first gold medal in singles of his career, but playing for his country once more brought the best out of del Potro. The four-hour, 26-minute contest was the longest best-of-three men's singles match of the Open Era. Del Potro had the edge for the first two sets, but couldn't break Federer in the second despite two excruciatingly patchy games on serve and then Federer dominated the tie break.
Slowly the match assumed the characteristics of a valiant rearguard action from del Potro. Federer had to hold serve 12 times in the final set - which alone lasted two hours and 43 minutes - to get the victory, although he was unable to serve out the match at 10-9, and it would take 16 more games for Federer to get the victory.
'Juan Martin did so well to hang in there,' Federer said. 'It was very physical at the end, but also mental. I feel horrible for Juan Martin, but he can be very proud.'
There would be some consolation for del Potro when he beat Novak Djokovic to claim the bronze medal (an achievement he would repeat at the 2016 Rio Olympics). Federer lost to Andy Murray in straight sets in the final and got the silver.