The intriguing battle between Roger Federer and Rafael Nadal looks set to continue in 2011 with both players still performing at their very best. While world rankings would suggest both were starting a downward slide, they both seem to produce their best tennis when it comes to the Slam events. Betting on tennis continues to evolve around them alone to the point that there is often daylight between them and the next tier in the betting.

Players are gearing up for the first major of the season, the Australian Open. Federer and Nadal are in Doha while many of the other players are in Australia for the Hopman Cup. In Doha, Nadal (13/10) leads the betting marginally ahead of Federer (8/5) with the next best Davydenko (10/1) and Tsonga (13/1).

Nadal has given himself a real workout in Doha playing in both the singles events and the doubles. Federer on the other hand is only playing in the singles. For Nadal, this could be a smart move since he always seems to play better when he has played long matches.

In Perth, Novak Djokovic is certainly on fire having won all of his matches without raising a lather. The Australian Open will certainly be well worth watching with those three in top form. Early betting on the Open reflects this with Nadal, Federer, Murray and Djokovic the only players under 10/1. The next best is Soderling at 25/1.

The interesting player in that quartet is Andy Murray. He has shown a lot of promise over the last three years, yet when it comes to the crunch he has failed to produce the goods. He is the only one of the four not to win a Slam event despite taking home several masters titles. Bookmakers are still showing a lot of faith in Murray by keeping him in the favoured group.  One thing is for sure, we are in for an interesting first Grand Slam event for 2011, and one feels it will be another classic Federer v Nadal final.