Garbine Muguruza celebrates.  [Photo/Agencies]

"Serena is a very powerful player and I just tried to fight as hard as I can."

For Williams it was a second straight loss in a Grand Slam final and it wrecked her hopes once again of winning a 22nd Grand Slam title to draw level with Steffi Graf for most wins in the Open era, since 1968.

She will now turn her focus on Wimbledon where she will be the defending champion and a six-time former winner.

"Congratulations to Garbine, she played really well today," said Williams, who confirmed that she had been slightly troubled by an adductor problem.

"I could have served better, made a lot of errors on return, but I did try hard out there."

The players took contrasting routes to get to the final.

Fourth seed Muguruza breezed through, losing just the one set, in her opening match, while Williams struggled past the quarter- and semi-finals amid talk of an injury or illness.