Rafael Nadal: Superstar surprised by return to year-end No. 1

The 31-year-old beat South Korean Hyeon Chung in the Paris Masters second round to open up an unassailable lead over old rival Roger Federer.

Rafael Nadal said that he had never expected to finish 2017 as the world number one, after securing the year-end top ranking for the fourth time on Wednesday.

The 31-year-old beat South Korean Hyeon Chung in the Paris Masters second round to open up an unassailable lead over old rival Roger Federer.

The Spanish legend started the year down at ninth in the rankings after an injury-plagued two years that saw him fail to reach a Grand Slam semi-final in 2015 or 2016.

"Of course it was not the goal (at the start of the year)," said Nadal.

"It was impossible for me to think about that when you are coming back from a tough period of time without playing tennis and with so many injuries in last couple of years.

"But yes, here we are, (it) happened. And very happy of course. Means a lot, no? After almost 10 years since the first time that I finished the year with this number."

Nadal first ended a year at the game's summit in 2008, before repeating the feat in 2010 and 2013.

The 16-time Grand Slam champion completed his rise back to world number one for the first time in over three years in August.

But Nadal said his achievement on Wednesday tasted sweeter than when he usurped Andy Murray three months ago.

"I think it's a very important achievement and is (an) important achievement in itself," he said.

"For me it has much more value (to) finish the year than being number one in the middle of the season.

"Both things are important but it's different."

A raft of injuries had left many thinking that Nadal was a spent force at the end of last year, but he stormed back to prominence with a five-set final loss to Federer at the Australian Open.

A 10th French Open title at Roland Garros followed in June, before he claimed his first Grand Slam crown away from his favoured clay in four years at the US Open.

"I had periods of time that I have been injured," Nadal added.

"I've had periods of time where I was not winning. And when that happened, of course I had doubts.

"But at the end of the day for me it's not about believing in yourself. It's (about) belief when you work.

"Then when you win, you believe in yourself."