Paris - Beaten French Open finalist Lucie Safarova on Saturday backed Serena Williams to complete the calendar Grand Slam in 2015.
World number one Williams won her third Roland Garros title and 20th career major with a tough 6-3, 6-7 (2/7), 6-2 win over the 13th seeded Czech.
Despite holding a 2-0 lead in the deciding set, the 28-year-old Czech then gave up the next six games to the rampant American.
Safarova saw enough to predict that Williams, having already secured the Australian Open in January, can go on and win Wimbledon and the US Open.
That would make her the first woman to complete the sweep since Steffi Graf in 1988.
"She's a great player. She has obviously the experience. She won all those Grand Slams already," said the left-handed Czech.
"I think she can do it. If she's on her best and in great shape, she's playing the best tennis."
Playing in her first Grand Slam final, Safarova had knocked out defending champion Maria Sharapova on her way to Saturday's title match.
She said that Williams showed little sign of the flu bug which had laid her low this week and with which she struggled during her three-set semi-final win over Timea Bacsinszky.
"She served amazing and was rallying very well. It may be question to her, but to me she seemed pumped and ready today."