Novak Djokovic launches his bid for a record 25th Grand Slam crown at Wimbledon on Tuesday as Barbora Krejcikova begins her title defence with major questions over her fitness on another sizzling day in London.

Novak Djokovic says he would like to keep playing tennis for several more years. But he also acknowledges it's impossible to know for sure whether he will even be back at Wimbledon again.

Novak Djokovic, the seven-time Wimbledon champion, returns to the All England Club with his sights set on getting past the all-time Slam record of Australia's Margaret Court and reaching unprecedented heights.

Only four men have won three Wimbledon titles in a row in the Open era, which began in 1968: Bjorn Borg, Pete Sampras, Roger Federer, and Novak Djokovic.

The 22-year-old Spaniard, riding an 18-match winning streak, opens play on Centre Court against Fabio Fognini as he seeks to join an elite group with three consecutive Wimbledon championships.