Friday 23 February 2018 00:17, UK
Stan Wawrinka's comeback from a six-month injury lay-off suffered a further setback when he was forced to retire in Marseille against World No 193 Ilya Ivashka.
The 32-year-old, a three-time Grand Slam champion, was 6-4 1-1 down to the Belarusian qualifier when he was forced to quit at the ATP 250 event.
Wawrinka, world No 13, decided to undergo knee surgery last August and was forced to miss the defence of his US Open title and the second half of the 2017 season.
The Swiss player has endured a testing start to 2018 - he has won only three matches - and lost in the second round of the Australian Open to American Tennys Sandgren on his return to the Grand Slam stage.
Wawrinka appeared to have regained some form with a run to the semi-finals in Sofia only to then suffer an embarrassing defeat to Dutch World No 259 Tallon Griekspoor in Rotterdam last week.
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