Thiem confident 'Big Three' will be toppled at Slams

World number four Dominic Thiem Thursday expressed confidence a new Grand Slam champion will be crowned in 2020 outside the big three of Novak Djokovic, Rafael Nadal and Roger Federer.

While the Austrian, Germany's Alexander Zverev, Greece's Stefanos Tsitsipas and others have had success at lesser tournaments, the big guns continue to dominate the majors.

Thiem, in Sydney for the inaugural ATP Cup team event, is one of the men tipped to make the breakthrough, with the first Grand Slam of the year, the Australian Open, just weeks away in Melbourne.

He said the younger players were getting close.

"I think we challenged them already a lot. We also beat them especially on Masters 1000 stages and the ATP Finals," said Thiem, who was runner-up to Tsitsipas at the ATP Finals in London in November.

"I think the last stage we have to conquer is the Grand Slam stage, and I really think we'll see a new Grand Slam champion in 2020.

"I really hope that it's me, but you cannot guarantee anything. There are also many other very strong guys who can achieve that.

"Maybe it's also not happening and Big Three are taking all four," he added.

"But we are trying everything to achieve top position, to achieve the biggest titles, Grand Slam titles."