A blockbuster television audience is expected to watch Nick Kyrgios’s historic Wimbledon semi-final clash against Rafael Nadal on Friday night, but 22-time major winner Nadal has cast doubt on whether he can play, after being urged to quit for the sake of his health.

Kyrgios is tipping his blockbuster with Nadal will be “the most-watched match of all time” after casting aside his domestic dramas to gatecrash the Wimbledon semi-finals for the first time, with the winner most likely to face Novak Djokovic in the final.