'The new generation has to bring something unique, as Federer, Nadal did,' said Agassi

The eight-time Major winner Andre Agassi believes that the young generation has to step in, improve their game and stop respecting Roger Federer, Rafael Nadal and Novak Djokovic.

The American praised Nadal and Federer, saying they have brought many unique things to tennis that have kept them competitive for years.

"The next generation is on its way. You look at Zverev and Thiem. These guys have realized they can't afford to respect the 'Big 3' as much as they did in the past. They have to improve their game more to challenge the top positions, which is a challenging task. The new generation that comes to the top has to bring something new and unique, like Pete Sampras, John McEnroe, Ivan Lendl and the 'Big 3' did.

When I faced Roger Federer in the 2005 US Open final, there was no safe place to put a ball on the court. He always had the best forehand, and he could stay in touch with Andy Roddick in the number of aces. Roger's serve, return, movements and net game were incredible; his versatility was so strong that he might have had five things individually better than everybody else on tour.

Rafael Nadal came after Roger and brought enormous spin that changed the game of tennis. His balls appear to be long before they land within the court at the last moment. That changes the position where you have to stay and equals many of those qualities I mentioned about Roger. Alongside that, Nadal's powerful movement, his strength and endurance are still unmatched," Andre Agassi said.