Interesting match. Federer only had one break point in the first three sets and failed to convert it. Then, on the brink of defeat, he managed to go from 2-5 to 7-5, breaking Djokovic twice in a row out of nowhere to get a fifth set. Serious choking by Djokovic, but Federer also raised his level when he needed to (e.g. when he was facing championship point on his own serve). It could go either way now.
If he can win this, it would be sweet revenge for those painful semi-finals at the US Open in 2010 and 2011, where Djokovic saved match points to beat him both times.