Sydney, Jan. 16 : Swiss tennis star Roger Federer believes achieving tennis''s holy grail, the calendar grand slam is possible as playing surfaces in the modern era have become less distinct.

The calendar grand slam includes winning the four majors, the Australian Open, Wimbledon, the French Open and the US Open in one year, a feat achieved by Australian great Rod Laver 40 years ago. Few will recall that Laver also won the all grand slams in one year in the non-open era.

"I think it''s possible still, to be quite honest, because conditions have slowed down," said Federer after he scraped past Spaniard Fernando Verdasco 6-3, 3-6, 7-6 (7-5) in two hours and 14 minutes yesterday in the Kooyong Classic to reach the final and keep his preparation for next week''s Australian Open - and a record-equalling 14 majors - on track.

"I don''t think Wimbledon is terribly fast any more, and the US Open and Australian Open feel pretty similar. If you''re on top of things, they can fall your way. Before, the grass and clay was too one-sided. You had basically the clay players and the grass players," the Sydney Morning Herald quoted Federer, as saying.

Federer said the difference between the playing surfaces was now becoming less distinct, he believed the calendar grand slam mission had been made tougher in the past by the vast difference between the way the game was played on grass and clay and the specialists that produced.

Federer said he loved being around Laver and the great Australian players "who have achieved so much in tennis and still are very humble".

In 1969, Laver became the most recent man to win the Australian, French and US Opens and Wimbledon in one year - seven years after he first achieved it. (ANI)