If there is one thing we've learnt from day nine of the Australian Open it's that clarification is desperately needed over the challenge rule.
After the David Nalbandian debacle the other day, confusion over when is acceptable to challenge a call reared its ugly head once again when Rafael Nadal took on Tomas Berdych.
At a crucial point in the first set, Nadal found himself cursing the lack of clear guidelines over the rules pertaining to when and when not is acceptable to challenge a line call.
Rafa's belated attempted challenge was ignored by umpire Carlos Bernardes, the Spaniard having been judged to have moved enough to signal he was ready to play the next point - from which Berdych brought up set point - before he challenged the call.
Cue much ire from Nadal, especially since he had a point (literally) - the ball was clearly out.
Yet it mattered not as his protestations fell on deaf ears. Needless to say, Berdych went on to claim the first set.
And Nadal's frustration was piqued yet further in the fourth set when, facing a break point while serving at 3-2, Berdych clearly played a backhand return of serve, moved as if to carry on the point, saw that his return was going out and decided to challenge.
With a shocking lack of consistency, Bernardes allowed the challenge with Nadal being forced to play a second serve when his first was shown by hawkeye to have, in fact, been out. In the crowd and Tramlines's opinion, justice was done when Nadal saved the break point and went on to hold.
Right or wrong though, tournament organisers using Hawkeye technology must clarify guidelines in order to prevent the likes of this spat, and the one which became the talking point of David Nalbandian's second round loss to John Isner.
If not, major tennis events are in real danger of becoming nothing short of farcical. If organisers are willing to embrace technology, with the aim of making the game fairer, they must go the whole hog and make it absolutely clear where they - and the players - stand on the issue.
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Caroline Wozniacki's defeat to Kim Clijsters might just be the best thing that has happened to the current - but not for long - incumbent of the world number one spot.
Shorn of the heavy expectation that comes the being the 'best player in the world', Wozniacki will now be able to concentrate on silencing her critics, and on becoming a better player.
Wozniacki's defeat to Kim Clijsters proved many things, not least that she is not the best player in the world.
Yet the ranking, which has become somewhat of a millstone around her neck, might prove liberating for the genial Dane.
At the very least, she will no longer have to answer persistent questions about whether she deserves to hold such a position, having never won a Grand Slam.
Instead, with some good coaching and plenty of application, she will be able to focus on improving the areas of her game that have so far held her back in the big tournaments.
And if she can succeed in doing so, maybe, just maybe, a Grand Slam title will not prove to be quite so elusive.
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Who's the most popular tennis player at this year's Aussie Open?
Tournament organisers have the answer, according to a poll on the official website: Roger Federer.
The Swiss Master took top spot ahead of Rafael Nadal, based on social networking sites. When fans tweet about their favourite players using a hashtag or they 'like' content on the tournament's official website, a points total is accrued.
The top two are followed by Maria Sharapova, Andy Murray, Novak Djokovic, Bernard Tomic, Lleyton Hewitt, Kim Clijsters, Caroline Wozniacki and Tomas Berdych.
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SHAMELESS PLUG OF THE DAY: The Davis Cup has a new home on UK television with British Eurosport securing a two-year deal to broadcast exclusive coverage of the World Group.
QUOTE OF THE DAY: "I don't think that me and Maria (Sharapova) are the only players who actually grunt. I cannot speak for any others. I only speak for myself. It's the way I am, the way I play, the way I used to play when I was a kid. And if you want a little bit more insight, I think it's the way that made me breathe, made me move. It's part of my movement." Victoria Azarenaka, who extended her winning shriek, sorry, streak to 10 matches with victory over Agniesszka Radwanska.
PHOTO OF THE DAY: What more needs to be said...?
RALLY OF THE DAY:
LOOKING AHEAD: Wednesday is Andy Murray time at the Australian Open- at least for British tennis fans. The Scot faces up to Japanese sensation Kei Nishikori for a place in the semi-finals. Meanwhile, Petra Kvitova kicks off the action on Rod Laver Arena against Sara Errani before Maria Sharapova meets surprise package Ekaterina Makarova. The night session sees David Ferrer do battle with Novak Djokovic for a place in the men's last four.