Hong Kong: American tennis legend John McEnroe said Tuesday that there are no likely challengers who could break Roger Federer and Rafael Nadal`s stranglehold on the game`s top tournaments.
"Federer and Nadal are two of the greatest players that have ever lived," McEnroe told reporters ahead of the exhibition Hong Kong Tennis Classic.
"I see excellent players, bordering on great players, but I don`t see them breaking and winning majors," he added.
The Swiss Federer and his Spanish rival have been engaged in one of sport`s greatest and most enduring rivalries, dominating the game for years.
Serbian world number three Novak Djokovic and Britain`s number four Andy Murray will have to "work harder than ever to compete against two of the most talented players that ever played tennis," McEnroe said.
"There`s no reason to believe these guys (Federer and Nadal) are not going to be around for the next few years," he added.
Djokovic lost to Nadal in last year`s US Open final, while Murray fell to Federer in the Australian Open decider.
Nadal stands at the top of the ATP rankings, some 3,305 points ahead of Federer, after a superb 2010 season when he grabbed the world number one spot as well as winning the French Open and Wimbledon singles titles.
The Spaniard goes into the new year having won nine major titles, trailing Federer`s all-time record of 16.
McEnroe, a seven-time Grand Slam singles champion, was speaking ahead of Wednesday`s start to the annual Hong Kong tournament, considered a lead-up to the Grand Slam Australian Open later this month.
The exhibition contest features teams of one male and two female players representing Europe, the Americas, Asia-Pacific and Russia.
McEnroe is teaming up with powerhouse Venus Williams to represent the Americas while Denmark`s Caroline Wozniacki -- the current world number one -- and retired Swedish superstar Stefan Edberg are playing for Europe.
China`s Li Na and Vera Zvonareva will captain the Asia-Pacific and Russia teams respectively.