Djokovic did not really have the momentum except for the earlier part of the match. Djokovic came out strong in the first set and won that, but then Nadal turned the momentum around and was the better player in the second set and seemed to be so during the third set also, but didn't take his set points in the third. The next day, Nadal started strong and won the fourth set, and seemed to be playing better in the fifth set, enough for Djokovic to growl in anger at his box at one point. More break points went for Nadal, and he eventually lost.
Momentum wise, Djokovic started the match strong and won the first set. The rest of the match, Nadal seemed to have the momentum until it slipped away at the end, although Nadal started 1-2 down in sets on the second day instead of 2-1 up in sets.