He's won MC, Barcelona and Rome in straights. Madrid and it's blue clay was the one aberration. Winning titles without dropping a set isn't easy so wel done Rafa - clay God in business so far this season.
Last player to take a set off him on red clay - Del Potro.
“But even so, amid the tornadoed Atlantic of my being, do I myself still for ever centrally disport in mute calm; and while ponderous planets of unwaning woe revolve round me, deep down and deep inland there I still bathe me in eternal mildness of joy.” - Melville, Moby Dick
Only Federer in the Roland Garros final (7-5) and Del Potro in the Davis Cup Final (6-1) managed to take sets off him in this period. Quite impressive, he hasn't even played that many tiebreaks either.