Nadal and Federer to meet in two exhibition matches

Rafael Nadal and Roger Federer will interrupt their brief off-season to face off in two exhibition matches before Christmas in Zurich and Madrid next month, it was announced on Thursday.

The world's two best players, both in London to compete in the ATP World Tour finals, will play in Zurich's Hellenstadion on Dec. 21 before flying to the Spanish capital to play the following day at La Caja Magica.

Proceeds from the best of three set matches will go to the players' charities.

"I always enjoy playing Rafa on the big stages and it is especially exciting when we can do it to help raise monies for our foundations," 16-times grand slam champion Federer said in a statement on Thursday.

The announcement of the exhibition matches comes as the ATP prepare for a series of board meetings in London in which they are expected to shorten the men's calendar -- a move favoured by both Nadal and Federer.

World number one Nadal, who boasts 14-7 record over Federer in competitive mathces, has only just returned from a shoulder injury which prevented him playing at the Paris Masters.

"It's their right to play these matches, especially as they're doing it for charity," ATP chief Adam Helfant said in London this week when asked if he agreed with players taking part in exhibition matches during the off-season.

However, the ATP could bring in rules regarding exhibition matches if they agree a two or three week lengthening of the off-season. "We are not looking to change the exhibitions or special event rules across the whole calendar, but I'm talking about this potential mandated period of rest across two or three weeks," Helfant said.