JesuslookslikeBorg. said:
this year was his best chance to win, cupcake draw, below par Federer in SF, and a surface not exactly lightning fast even if it did speed up at the end of the tourney..a bit.
MegaRafa of 2013 couldn't do it..so can he ever win the Year End Finale ?.
The surface is utterly horrible for his game. I really wouldn't take his failures there too seriously, because he is so disadvantaged by the low-bouncing court that it is basically unfair to him. Probably no other court (certainly not at any Grand Slam or Masters 1000) favors Nadal's opposition over him more than the court at the O2. He doesn't really have the game for succeeding against the very best on it, if they are playing to their potential.
That said, I could see him winning the event once, at some point, if some things fall into place for him. With the young generation being so weak, he'll probably play in the World Tour Finals another 7 to 10 times, so you'd think that he could pull it off once.