Roger Federer finished the 2013 campaign ranked sixth in the ATP world standings. Sixth! That is not a misprint, but more a sign of the times.
Since his success at Wimbledon back in 2003, Federer had won at least one Grand Slam every year, with the exception of 2011. Even then he made up for that disappointment by claiming the ATP World Tour Finals title.
It meant that when he lost out at the semi-finals stage of this year's Australian Open to Andy Murray in January, the alarm bells were not sounded - after all, there were three more Slams left to contest.
However, soon after, it became apparent that some of R-Fed's form had deserted him.
In recent years he had been used to losing out to the likes of Rafael Nadal, Novak Djokovic and Murray, but all of a sudden, other players on the Tour started to come out on top from their matches with the former world number one.
His form improved at the Rome Masters later that month where he lost in the final to Nadal, but it failed to inspire a positive showing at the French Open. Having reached the last eight, he was then knocked out by home favourite Jo-Wilfried Tsonga.
Nevertheless, that exit left Federer with more time to prepare for the grass courts of Wimbledon. The Swiss warmed up for SW19 in positive manner by winning in Halle courtesy of a three-set victory over Mikhail Youzhny.
No-one was prepared for what happened next, though. Federer got his campaign at Wimbledon off to a decent start when he dropped just five games during his win in the opening round against Victor Hanescu. Next up was Ukrainian Sergiy Stakhovsky, who caused one of the tournament's biggest shocks when he pulled off a four-set success. Not since 2002 had Federer failed to reach at least the quarter-finals in the English capital.
Another early exit at Flushing Meadows followed, this time in the fourth round to veteran Spaniard Tommy Robredo. It meant that Federer would end the campaign having not been able to add to the 17 Grand Slam titles to his name.
Furthermore, his place at the season-ending World Tour Finals was not guaranteed - something that was not helped by losing in the second round of the Shanghai Masters to Gael Monfils. He reached the final of the Basel Open and the semi-final of the Paris Masters, though, which eventually secured his spot in the top eight.
Despite an opening match loss to Djokovic, wins over Richard Gasquet and Juan Martin del Potro set up a semi-final clash with Nadal at London's O2 Arena. It would be a routine 7-5 6-3 win for Nadal, who had previously struggled against Federer indoors.
Don't mention retirement to 32-year-old Federer, though, as he recently said: "The thing is that when you stop you are still so young, so why stop early? Why just walk away? I can still choose, and I pick to play. As long as I have this choice, I'll keep on playing."
If the last few months are anything to go by, 2014 could be a difficult year for Federer. Having said that, if anyone can defy the odds, it's him. Watch this space.