check out: mic'd up Dec 2016 warm-up and practice set 125 degree heat in DubaiI am dumbfounded by what I have seen this year. Does this guy ever get tired? People used to talk about Nadal and Djokovic's stamina. Federer at 35 seems to have more stamina than Nadal and Djokovic at 30 and 29. Hats off!