Nick Kyrgios's comeback match following a five-month injury layoff ended in defeat after he was beaten 7-5 6-3 by China's Wu Yibing in the opening round of the Stuttgart Open on Tuesday.
The 28-year-old Australian underwent surgery on a knee injury in January and had not competed this season.
"Be patient with me my fans please. It's a process to get back to where I was. I know it's hard for you to see me perform like today, but I need more time and hopefully can get back to where I was," he posted on Twitter after the match.
The Australian, who was beaten by Novak Djokovic in the Wimbledon final last year, had last played a singles match in October in Tokyo and pulled out of the Australian Open in January in the leadup to the tournament.
He was forced to delay his comeback and missed the French Open due to a foot injury he sustained during the theft of his car last month.
He now faces a race to get back to his best in time for Wimbledon which begins on July 3.
Sherfane Rutherford struck an unbeaten half-century and Gudakesh Motie produced a brilliant display of spin bowling as West Indies thumped England by 30 runs in a Twenty20 World Cup Group C encounter on Wednesday.
Australia launched their Twenty20 World Cup campaign with a commanding 67-run victory over Ireland in Colombo on Wednesday, powered by four-wicket hauls from Nathan Ellis and Adam Zampa.
Tottenham Hotspur have sacked manager Thomas Frank after eight months in charge, the Premier League club said on Wednesday, after a woeful run of results left the north London club hovering five points above the relegation zone.
South Africa survived Kagiso Rabada's final-over meltdown against Afghanistan and then a double Super Over drama before prevailing in a heart-stopping Group D match of the Twenty20 World Cup on Wednesday.
Pakistan opener Sahibzada Farhan has hit a swift half-century as the 2009 champions comfortably beat the US by 32 runs on Tuesday, clinching their second straight Group A win in the Twenty20 World Cup.