Andy Murray’s fans are still hoping that the world No. 1 will flick a switch next week, and discover some much-needed form against his first-round opponent Andrey Kuznetsov.

But anyone who saw a grouchy and out-of-sorts Murray practising on Court Suzanne Lenglen on Friday would have felt serious reservations about his chances of going deep at this year's French Open.

Ivan Lendl spent the early part of the session seated in the stand as Murray swore and threw his racket down. Day-to-day coach Jamie Delgado found himself on the end of the sarcastic quips and glares that have surfaced more and more often in recent weeks. At times, Murray’s practice partner Pablo Cuevas must have wondered what was going on across the net.

In his darker moments, Murray has often brought to mind the PG Wodehouse line “It is never difficult to distinguish between a Scotsman with a grievance and a ray of sunshine.” But experienced camp followers still rated this one of the most unpromising sessions they had seen.

Afterwards, Murray came to the interview room and played down the significance of a virus that he contracted at the end of last week – his third bout of illness since the start of the season.