MOSCOW: Former world No. 3 Nikolay Davydenko announced his retirement on Thursday at the age of 33.

The Russian, who won the ATP World Tour Finals title in 2009 and helped his country win the Davis Cup in 2006, said injuries had forced him to end his 15-year career.

“I had a lot of injuries over the last few years,” Davydenko told a news conference in Moscow.

“They are still causing me discomfort. The time has come: I am officially announcing my retirement as a professional sportsman.” Davydenko, never one of the sport’s great showmen, consistently mixed it with the big guns and famously beat Roger Federer at the 13th time of asking in the semi-finals of the Tour Finals in London five years ago before downing Argentina’s Juan Martin del Potro in the final.

His best year on tour, however, was in 2006 when he won five titles and reached the US Open semi-final, rising to third in the world rankings.

He also reached the US Open semi-finals the following year and made the last four at Roland Garros in 2005 and 2007.

In total, the baseline specialist known for his speed around the court and durability won 21 titles.

US Open champion Marin Cilic was made to work hard before he earned a 6-3, 3-6, 6-3 win over 128th-ranked Russian journeyman Evgeny Donskoy to reach the quarter-finals of the Kremlin Cup on Wednesday.

Cilic was pushed to the limit at times but claimed victory in just under two hours to keep alive his hopes of qualifying for next month’s ATP Tour Finals.

The Croatian second seed had the greater composure in the decider, breaking wildcard Donskoy three times while just about managing to keep his own serve functioning, despite being broken twice by the 24-year-old Russian.

“I am generally happy with today’s match,” said Cilic, who will next face either Tommy Robredo or Filip Krajinovic.

“In the first match of a tournament, I always feel a bit rusty.

“I was really surprised by my opponent. I had never played Donskoy before and had not even trained with him. He played a great game today.” The Croat currently stands sixth in the “Race to London” for the end-of-season ATP World Tour Finals which will feature the top eight players.