Dinara Safina (right) with Madrid Open winner Maria Sharapova.

Former world number one Dinara Safina, whose career was wrecked by a series of back injuries, formally announced her retirement in a ceremony at the Madrid Open on Sunday.

The 28-year-old Russian, the younger sister of former men’s number one Marat Safin, won 12 singles titles including Madrid and reached three grand slam finals but has not competed since losing in the second round in the Spanish capital in 2011.

“I took as much time as I could,” Safina was quoted as saying in an interview.

“I am not this kind of person that I would say no, and then I would think and maybe come back,” she added.

“I was having so much pain in my back, it was tough, everything was hurting me.

“Also when you don’t compete your body is different, once you stop your body is in a big shock.”

Asked how she had been filling her time the past three years, Safina said: “Nothing that’s so serious but a little bit of everything”, including studying, working with her brother and a spot of commentating at the French Open.