The 2013 ATP World Tour season came to an end on Monday night with the World Tour Finals. No.2 Novak Djokovic defeated top ranked Rafael Nadal in straight sets to win the London indoor tournament.

“I didn’t play a bad match, but not enough consistently,” Nadal said after the loss. “That’s why the result. He was more consistent than me on the serve. In the end, that makes a big difference, because he doesn’t let you play with more calm the rest of the shots.”

Despite the disappointing end to 2013, Nadal had an incredible run this year. He won 10 titles, which nearly matched his career-high of 11 in 2005. Even when the 27-year-old wasn’t winning championships, he made good showings, reaching the finals on four other occasions. All signs point to Nadal having another big year in 2014.

If 2013 proved anything, it’s that it will take a lot get Nadal off his game. The Spaniard returned to the court in February after missing seven months with knee injuries. He didn’t seem to miss a beat following his knee issues, eventually taking the No.1 spot in the rankings. It was a sharp ascension for Nadal, who was at No.5 when he made his 2013 debut in February.

In another year, it might be more difficult to be certain that Nadal would come back as good as ever. However, there aren’t many tennis players who have a legitimate shot of knocking him off as the best player in the sport. He and Djokovic will likely be going back-and-forth for the whole year, but after that, there isn’t much legitimate competition.

Roger Federer is one of the all-time greats, but he’s also passed his prime. Nadal was dominant against his rival this year, losing just one set in four head-to-head matches. Federer had a few major letdowns this year, including a surprising loss to Tommy Robredo in straight sets in the fourth round of the U.S. Open. Andy Murray won’t have an easy time challenging Nadal and Djokovic. The Scot is recovering from back surgery that he underwent in September.

Nadal won two Grand Slam titles in 2013. The start of next season is still a few months away, but it seems like he’s almost guaranteed to win at least one Grand Slam tournament. This year, he won his fourth straight French Open title, and his eighth in the last nine years.