Murray v Nadal
Murray might take this one, maybe in two but more probably in three sets. It's no banker but I'll put a small wager on Murray in three sets.
Djokovic v Federer
Reviewing the Berdych match, I don't think Federer played all that well and has made a lot of u/es this week. Allied to the starly contrasting effort each man made, I got for Nole on this one, quite possibly in two sets.
Final: If it works out as I suspect in the semis I tip Djokovic for the title.
Clearly just opinions and highly debatable, but there's my tip set down.