MADRID -- The father of Australian tennis player Bernard Tomic has been charged with assaulting his son's hitting partner before this week's Madrid Open.

A Madrid court said Monday that John Tomic, who is also his son's coach, disputed the charges and will face trial May 14.

Tomic's hitting partner, Thomas Drouet, told the Australian newspaper the Herald Sun that John Tomic head-butted him Saturday during a scuffle outside the players' hotel.

At a hearing Monday, the court said it could not hold a trial immediately because John Tomic disputes the facts as presented by prosecutors. Under Spanish law, a speedy trial can be held if both sides agree on the facts. Such an agreement can lead to reduced penalties.

Tennis Australia said it was working with the ATP tour in investigating what happened.

Tomic lost in straight sets to Radek Stepanek in the first round Sunday.