Rafa Nadal put his students to the ultimate test.
The Aussie jumps all over Zverev, who was seen out partying six days after promising to self-isolate.
Tunisian player also fined $7,000.
Former No. 1 says shift from US Open hard-court to Madrid clay is hazardous.
The uncle of Rafael Nadal says that the ATP's schedule is going to be extremely tough on the older players.
The final will remain in Budapest and take place from April 13 to April 18 2021
Novak Djokovic's coach is latest figure from Adria Tour to contract the virus.