Serena Williams reacts after her match.  [Photo/Agencies]

But with weather conditions improving after one of the rainiest Roland Garros tournaments on record, it was a different, more focussed Williams that got the final underway with a love service game.

Muguruza replied in kind as two of the biggest and best servers in the women's game went head to head.

The 22-year-old Spaniard had to battle hard to level at 2-2, saving two break points along the way, but she then grabbed the first break of the final thanks to a loose game from the American culminating in a double fault.

Muguruza, who lost to Williams in the Wimbledon final last year, moved 4-2 ahead, but she lost her range two games later to allow the American to level the score.

The tall Spaniard was matching Williams for power and when the title-holder opened the 11th game with a double fault she seized the opportunity to apply some added pressure on her opponent.

Her tactics paid off with Williams failing to cope with a series of explosive baseline groundstrokes.