John McEnroe and Bjorn Borg are dissecting the career of Roger Federer and picking the single moment that stands out in an illustrious career which draws to a close at the O2 Arena this weekend.
Looking back on 20 Grand Slam titles and 103 tournament wins, the instance that springs to mind for McEnroe is the 2008 Wimbledon final loss to Rafa Nadal, which lasted nearly five hours.