London - It was a time when John McEnroe vied each year for the Wimbledon title - but his activities away from the championships would have shocked his fans.

The former tennis world No 1 would relax between matches by smoking marijuana with his pop-star friend Chrissie Hynde.

The revelation comes from Pretenders singer Hynde, who said: “Way back in the days when he was doing Wimbledon, he would always call me because he knew I had pot. He used to come around and hang out.”

McEnroe first competed at Wimbledon in 1977 aged 18, when he got to the semi-final, and won the tournament in 1981, 1983 and 1984. Hynde’s band found success in the same period, topping the charts with their single Brass In Pocket in 1979.

While Hynde’s memories will surprise fans of McEnroe who know him only from his more sober image nowadays as a BBC commentator, he was once the “bad boy” of tennis, notorious for his on-court confrontations with umpires.

He is an able guitarist and he and Hynde remain good friends.

McEnroe has appeared on stage with The Pretenders numerous times and he plays on her recent solo album, Stockholm.

In an interview with NPR, a US radio station, Hynde, 62, said she tried to encourage McEnroe to quit tennis because he has “such personality” when he plays the guitar.

She said: “That’s what it’s all about with rock ‘n roll, individual personalities, not if it’s good or bad.”

McEnroe has admitted using drugs during his marriage to former actress Tatum O’Neal, with whom he had three children before divorcing in 1994.

In her memoirs, O’Neal said McEnroe “kept drugs around for hospitality... like having a wine cellar”.

Last month their son Kevin, 27, was charged after police saw him allegedly buying cocaine and prescription pills in New York.