Rafael Nadal called for tougher sanctions against players who abuse tennis officials in the wake of the controversial suspended sentence handed down to Alexander Zverev.

Spanish star Nadal said that as a friend and practice partner of Zverev, he had no desire to see the German Olympic champion receive a stiffer sentence for his violent outburst at last month’s Mexico Open in Acapulco. But the 21-time Grand Slam champion said that as a fan of the sport, tougher sanctions were needed. Zverev was disqualified from the tournament for repeatedly smashing his racket into the umpire’s chair before verbally abusing the official.