djokovic became the first player to win the opening three atp world tour masters 1000 .
the 27-year-old serb did not have it all his own way in a rain-hit match against berdych , who had forced a break in the very first game and later rallied to force a deciding set .
djokovic was 3-2 up in the second before rain took the players off court for the best part of an hour .