Current Rafa is currently playing some excellent tennis against Berdych and will most likely be the final opponent for the winner of the second SF (currently winning 7-6 4-1*).
Nishikori is playing really well, and will be very tough for Andy I think. For Andy to beat him would probably be his best victory on the clay.
SF: (2) Andy Murray WR 3 defeated (4) Kei Nishikori (JPN) WR 5 by 3 & 4
******
Final: (3) Rafael Nadal (ESP) WR 4 (CH = 1 on & off since August 2008) vs (2) Andy Murray WR 3
The head-to-head is 5-15 Nadal. Andy's played him six times on clay (most recently in the semis at RG last year, when Rafa beat him in straight sets) & never beaten him...
A win for Andy over Rafa in the final would be distinctly unhelpful to Rafa's chances of being number 4 seed for the French Open ( Andy will be no 3 ) with the discussed potential for him to be left outside the top 4, as a QF opponent to one of the top 4 seeds.
But hey that can work out however in time. For now, go Andy !!!
I worry that he won't have enough left in the tank. He's had a horrifying schedule this last two weeks, not a good platform to face the Clay Monster even if he is not quite back to his best. Still it must have done wonders for his confidence.