Serena Williams, an indomitable force for the best part of two decades, will launch her latest bid for a record-tying24th Grand Slam at Wimbledon next week as the tournament's biggest question mark after ending a year-long absence from competition.
Williams played doubles at the Eastbourne International with Tunisian Ons Jabeur this week but has not played in a competitive singles match since limping out the first round at Wimbledon last year.
Her return to Wimbledon, where she has won seven singles titles, has left even the sport's foremost experts stumped on what fans can expect.