Serbian professional tennis player Novak Djokovic couldn't be so thankful for the 2013 season. Djokovic may have lost his World No. 1 rank to Rafael Nadal, but he sure has a lot of things to be grateful for.

"What a great way to finish the year," Djokovic wrote on Instagram. "I may not be number 1 but Rafa definitely deserves it," he added. "A big thank you to everybody who has supported me all throughout the year, love you all #nolefam," wrote Djokovic.

Djokovic has defeated World No. 1 Rafael Nadal, 6-3, 6-4, on Monday in the Association of Tennis Professionals (ATP) Finals in London. This is his third victory in the ATP Finals, and Djokovic has remained unbeaten since the U.S. Open.

"This was just the best possible ending," Djokovic told ATP. "Now, I really feel that my season was really good, after the fall run and all," he added. "This is definitely a great way to boost my confidence for the beginning of the next season," said Djokovic.

Djokovic started the 2013 season by defeating World No 4 Andy Murray in the finals of the Australian Open. It was his third consecutive win in the said tournament and the sixth Grand Slam of this professional tennis career. He had also triumphed over Tomas Berdych in the finals of Dubai Tennis Championships in March, giving him his 36th professional singles' title.

He has defeated long-time rival Rafael Nadal in the finals of Monte Carlo Rolex Masters, and it was the first time for Djokovic to have won in Monte Carlo.

All throughout his entire tennis career, Djokovic has faced Nadal 39 times. Djokovic's victory against Nadal on Monday gave him a split of six matches against the Spanish athlete in the 2013 season. Nadal still leads, 22 to 17. Who knows, maybe Nole would own the head to head with Rafa soon.

Congratulations to Novak Djokovic for a strong finish.