After today, it's a little trickier to pick this one. But here is all the relevant H2H information:
Fed leads the H2H 9-3
http://www.atpworldtour.com/Players/Head-To-Head.aspx?pId=F324&oId=T786
Roger has won five of the last six meetings, including the most recent a QF at this year's AO. Roger has won the only clay meeting in the 2nd round of the 2011 Rome Masters.
vs.
Fed leads the H2H 9-3
http://www.atpworldtour.com/Players/Head-To-Head.aspx?pId=F324&oId=T786
Roger has won five of the last six meetings, including the most recent a QF at this year's AO. Roger has won the only clay meeting in the 2nd round of the 2011 Rome Masters.

vs.