Timeline of Roger Federer`s troubled 2013

London: Roger Federer`s troubled 2013 season came to a suitably downbeat conclusion with a semi-final loss against Rafael Nadal in the ATP World Tour Finals on Sunday. Here AFP Sports looks at the low points of the Swiss star`s worst campaign for over a decade:

January - Loses in Australian Open semi-final to Andy Murray.

February - Beaten in Rotterdam quarter-finals by Julien Benneteau, breaking a run of 28 consecutive last-eight wins against players outside the top 10.

May - Thrashed 6-1, 6-3 by Rafael Nadal in Rome Masters final, sending him into the French Open without a title in the year for the first time since 2000.

June - Crashes out of the French Open quarter-finals in straight sets against Jo-Wilfried Tsonga.

June - Defeats Mikhail Youzhny to win first and only title of 2013 at Halle and 77th career trophy to tie John McEnroe at number three in Open Era title-winners list.

June - Hits a new low as the defending champion loses to world number 116 Sergiy Stakhovsky in second round at Wimbledon. It is Federer`s earliest defeat at Wimbledon since 2002 and his earliest loss at a Grand Slam since losing in the French Open first round in 2003. The result ends Federer`s run of 36 consecutive Grand Slam quarter-final appearances.

July - Appearing in Hamburg for first time since 2008, Federer loses to world number 114 Federico Delbonis in quarter-finals. It is just the 12th time in his career he has lost to an opponent outside the top 100.

September - Fails in his bid to reach his 41st Grand Slam quarter-final when Spain`s Tommy Robredo sweeps to a surprise straight sets win in the US Open fourth round.

October - Announces the end of his coaching partnership with Paul Annacone, who had worked with him since July 2010.

November - Suffers 22nd career defeat to Nadal to end year with a loss in the semi-finals of the ATP World Tour Finals.

2013 match record: P62 W45 L17