Cape Town - ATP Tour commentator Robbie Koenig says Roger Federer still has the belief that he can add to his record Grand Slam tally.
READ: Koenig expects Djokovic to dominate
The Swiss world No 2 currently holds the record for most Grand Slam titles won - 17. His tally is three ahead of Rafael Nadal and Pete Sampras, who share second spot.
Koenig, who spoke exclusively to Sport24 on Wednesday, agreed that Federer adding to his Grand Slam tally was arguable the toughest question to answer in tennis.
The Swiss ace turns 34 later this year and his last major title came at Wimbledon in 2012. In fact, since the turn of the decade, Federer has only bagged two Grand Slams - his 2010 Australian Open final win over Andy Murray being the other.
After a below par 2013 season in which he was plagued by a back injury, Federer roared back in 2014. He won five ATP titles as well as landing the Davis Cup with Switzerland. It enabled Federer to move up to the No 2 ranking in the world, almost eclipsing Novak Djokovic for top spot late last year.
He started 2015 brightly, beating Canada's Milos Raonic in the final of the Brisbane International. It was his 83rd career title and also his 1 000th match win on the ATP Tour.
But Federer came unstuck at the year's first Grand Slam in Australia, surprisingly losing in the third round to Italy's Andreas Seppi.
After coming agonisingly close in last year's Wimbledon final, losing an epic five-setter to Djokovic, as well as a semi-final exit at the hands of eventual champion Marin Cilic at the US Open, questions were again raised if Federer's chances at more Grand Slam glory had gone begging.
But Koenig said the Swiss maestro would not be playing if he didn't believe he could win another Grand Slam.
"Federer has been there and there abouts in the last year. For me it's all about how he's feeling physically," said Koenig. "He still believes he can win it, 100%. When you've done as much as he's done, then you still believe."
Koenig though admitted that Federer's age would count against him.
"When you get over 30, you get off days and on those off days you lose, which is not always the case when you are in your prime."
However, Koenig felt Federer's record may be safe, predicting Nadal would start to find it more and more difficult to continue his dominance.Follow @RobKoenigTennis on Twitter
"I don't think so," Koenig responded when asked if he felt the Spaniard would catch Federer's record major tally.
Nadal, 28, was soundly beaten by Czech Tomas Berdych in the quarter-finals at the Australian Open and has struggled with numerous injuries in the last while.
"It's getting tougher for him. Every time you lose, the guys in the locker room start believing more and I think more players are starting to believe that they can beat him (Nadal)."
Djokovic secured his eighth major when he beat Andy Murray in the Australian Open final last Sunday.
Koenig said he expected the Serbian to dominate tennis for at least the next three seasons, but also does not see him overtaking Federer as the most decorated champion in the history of the game.
"I think Djokovic will win at least two majors for the next three years. Two majors a year from the start of 2015 would give him 13 majors in total," said Koenig.
Robbie Koenig is a former South African professional tennis player and current commentator on the ATP World Tour.