When Novak Djokovic went on an amazing run in 2011, winning three Grand Slam titles to announce himself to the world with one of the best years ever in tennis history, you felt such a year would be a one-off, surely.
Step up 2015.
Djokovic has been near unbeatable again this year, and even if he missed out on a calendar Grand Slam, owing to his loss in the final of the French Open to Stanislas Wawrinka, the Serbian showed, yet again, why he is far and away the best player in the world right now.
After reaching the final of the first three Grand Slams, winning two of them – Australian Open and Wimbledon – Djokovic added another major title to 2015, beating Roger Federer in four tough sets 6-4, 5-7, 6-4, 6-4.
"It's been an incredible season," Djokovic said. "I'm very fortunate to experience a great success this year. The season is not over, but the Grand Slam is over. The biggest tournaments that I have played this year, as anybody else, and I won three out of four. It's more than I could ask for, definitely.
"Of course I do have lots of expectations and high ambitions whenever I'm approaching the Grand Slams or any other tournament, but, now actually sitting down here with this trophy and reflecting on what I have achieved, it's quite incredible. So I'm definitely very satisfied and proud of that.
"I think it's definitely more difficult to repeat something like that than actually doing it for the first time again. I'm a different player, a different person today than I was 2011.
"As a father and a husband, you know, experiencing different variety of things in my life, it's completely different approach to tennis today.
"I feel more fulfilled. I feel more complete as a player today than I was in 2011. Physically stronger, mentally more experienced, and tougher, as well. Trying to use the experience from before into every match that I play, and especially the big ones."
Despite all his recent achievements – this US Open title was Djokovic's 10th Grand Slam – the world number one is still not the most popular player on tour – nothing like Federer or Rafael Nadal, who always seem to have the crowd supporting them,
In this US Open final against Federer, Djokovic only had a handful of fans supporting him, the rest, vast majority, was all in for the Swiss.
"There was a lot of support for Roger," Djokovic added. "There was some for me. I mean, for sure, I tried to focus on the ones that were supporting me.
"But I can't, you know, sit here and criticize the crowd. On the contrary, you know, I think it's logical to expect that a great player and a champion like Roger has the majority of the support anywhere I play him. I would say super majority of places around the world are going to give him that support.
"Now, percentage-wise, more or less, I don't know. I'm not there to judge who is supporting more or less. I'm there to play tennis. I accept the fact
"Everybody has a choice to support a player that they want to support, and he absolutely deserves to have the support he does because of all the years and success that he had and the way he carries himself on and off the court. No question about it.
"Me, I'm there to earn the support, and hopefully in the future I can be in that position."