French Open 2016: Serena Williams not ready for final curtain

Williams's latest attempt to equal Steffi Graf's Open era record of 22 Grand Slam titles was thwarted by Garbine Muguruza in the French Open final.

Paris: Serena Williams is closing in on her 35th birthday and has just suffered back-to-back Grand Slam final losses for the first time, but the American superstar is not ready to be dethroned any time soon.

Williams's latest attempt to equal Steffi Graf's Open era record of 22 Grand Slam titles was thwarted on Saturday by Garbine Muguruza in the French Open final.

Back in January, Angelique Kerber pulled off a similar shock to snatch the American's Australian Open title while in New York last September, Williams's hopes of a calendar Grand Slam were upended by Italian journeywoman Roberta Vinci in the semi-finals.

So Williams's Grand Slam haul has stalled at 21, but she will still start as favourite to win a seventh Wimbledon when the third major of the year gets underway in three weeks.

"The only thing I can do is just keep trying," said Williams, who was attempting to win a fourth French Open after 2002, 2013 and 2015.

"In Australia, Ann Kerber made 16 errors in three sets, you know, so what do you do in that situation? Today Garbine played unbelievable. It's definitely something I want to dissect and see what I can learn from that and what can I do to get better from it."

Williams has been down and out before and bounced back in style.

In 2011, she underwent two foot surgeries and fought life-threatening blood clots on her lungs.

Her absence from the tour saw her world ranking slip to 103.

In 2014, she lost in the fourth round at the Australian Open, second round at the French Open and third round at Wimbledon but hit back with the US Open.

In between, she won 11 WTA titles in 2013 and put together a 34-match win streak between Miami and Wimbledon.

Last year, when she collected a sixth Wimbledon, it allowed her to celebrate a second "Serena Slam" of all four majors at the same time.

She had already achieved a first Slam sweep in 2002.

Despite her record and status as one of the greatest players of all time, there were, however, obvious problems in a damp and chilly Paris, hinting that her sheer power is possibly being diminished.

Serena finished top of the pile for aces served at 36 and sent down the joint fastest serve of the event at 196km/h in Saturday's final. But she had one of the lowest first serve percentage rates at 60% and managed to convert only 30 of 73 break points over the two weeks.

Her team and even her rivals insist that the American, despite being in her third decade on tour, is not finished as a force in the game.

Her French coach Patrick Mouratoglou has no doubts that she will reach the magical figure of 22.

"Serena was far from her best level today," Mouratoglou told eurosport.Fr.

He has masterminded eight Slam titles in her last 16 tournaments compared to 13 from 47 before they hooked up after a first round loss at the 2012 French Open,

"It will take as long as it takes, but Serena will win a 22nd Grand Slam. It's not easy to break records, it wasn't easy for her to get to 18 (the number won by Chris Evert and Martina Navratilova)."

Muguruza's coach Sam Sumyk was also refusing to write off the American.

"It's not the end of Serena. She will be around for a long time. She is a fantastic player, we need her."