Serena Williams has withdrawn from this month's season-ending WTA Finals in Singapore citing a persistent shoulder injury, the world number two said on Monday.

The 22-times grand slam singles champion has played only eight tournaments this year and lost her spot at the top of the world rankings to German Angelique Kerber.

"It's been a really tough year for me, dealing with these shoulder injuries. My doctor insists that I stay home and heal it. I only have wonderful memories of playing in Singapore and I will really miss my fans," the 35-year-old tennis player said.

The world famous tennis player has been nursing injury since her last winning Wimbledon.

Coached by her father Richard Williams and mother Oracene Price also working with Patrick Mouratoglou, Williams began playing at age 5 at public courts in Compton, California.

The American professional tennis player is regarded by some commentators, sports writers, tennis players as the world's most successful tennis player of all time.