Tennis fans were out enjoying a perfect Australian Open day in the sun.(Nine) As well as all the standard tennis merchandise this year, you can also buy an Australian Open mask - which may become a collector's item and unnecessary next year. Tonight, all eyes will be on Ash Barty as she takes centre court. For those keen to head courtside - John Cain arena tickets are $49 weekdays and $59 weekends, the same price as a ground pass last year. READ MORE: Crowds were treated to an array of tennis superstars.(Nine) Novak Djokovic of Serbia watches the Men's Singles first round match between Filip Krajinovic of Serbia and Robin Haase of the Netherlands.(Getty)