Andy Murray's return to the clay proved to be a chastening experience as he lost in straight sets to Stan Wawrinka in the French Open first round.
The 33-year-old Scot was well below the level of 2015 champion Wawrinka, who eased to a 6-1 6-3 6-2 victory.
Murray's exit came after British number one Dan Evans lost to Japan's Kei Nishikori in a fluctuating five-setter.
Evans has lost on all three appearances in the main draw at Roland Garros after a 1-6 6-1 7-6 (7-3) 1-6 6-4 defeat.
British number three Cameron Norrie and qualifier Liam Broady are left to carry the flag in the men's singles.
Murray out of sorts on clay return
Excitement and a sense of disbelief greeted the draw which pitted Murray against fellow three-time Grand Slam champion Wawrinka - who the Scot faced in his last match on clay over three years ago.
For Murray, it was a remarkable twist of fate which even left him "amused". He had not played on the surface since a brutal five-set semi-final against Wawrinka at Roland Garros in June 2017.
That proved to be the start of the hip trouble which left him needing two major surgeries and on the verge of retirement last year.
Wawrinka, 35, has also seen his career stalled by a knee injury in recent years and it led to plenty of intrigue about how a poignant reunion between the two veterans at Roland Garros would pan out.
Ultimately, it did not end up being much of a contest as 16th seed Wawrinka ruthlessly dismissed an out-of-sorts Murray.
The Briton had beaten Wawrinka when they met in the European Open final in Antwerp in October, but a repeat result never looked likely.
The Swiss has climbed back up the rankings after finding form and fitness, showing why in a one-sided first set where he broke serve three times and won two thirds of the points.
Murray's first-serve percentage was down at a lowly 21% and that was punished by Wawrinka, whose heavy ball-striking was too much for Murray to handle.
Even though Murray's service game slightly improved, he continued to look flat and unable to rouse the spirit which has seen him turn matches around so often in the past.
Afterwards, Murray said he was trying to be calmer on court after regularly showing his frustration during matches in the recent Cincinnati Masters and US Open.
"It was something that was brought up to me and I tried to sort of keep my emotions in check," he said.
"I don't know whether that affected me in any way or not, but that was probably why it was quieter than usual."
Wawrinka maintained his level in the second and third sets as he continued to punch holes in Murray's defence, ending up with 42 winners as he cruised to victory in one hour and 37 minutes.
The match was played on a cold evening under the new floodlights on an open Court Philippe Chatrier, but Murray said the conditions were not a factor for his below-par performance.
"I didn't play well. I served under 40% first serves in the court, which is just not good enough against anyone, and especially someone as good as Stan," he said.
"You want to be serving in the 60%, that sort of region. You won't see many players serve under 40% the rest of the tournament."
Russell Fuller, BBC tennis correspondent
Murray had not played a clay-court match for more than three years before this one.
He prioritised the US Open while Wawrinka was getting in some clay-court practice on the Challenger Tour. But the difference between the two was still stark.
Murray accepts he will never physically be the same as he was, and performances like this do make you wonder whether he can ever have the impact he would dearly love to have at Grand Slams.
Motivation may come in the form of Sweden's former world number one Mats Wilander, who asked on Eurosport whether Murray still has the right to be taking wildcards from young players.
The aim for the rest of the season is to play as much as possible - starting with back-to-back indoor tournaments in Cologne next month.
Evans still searching for an elusive Roland Garros win
Evans admitted he could not have been handed much tougher a draw than Nishikori, who is ranked one place below the Briton after injury problems at 35th in the world.
So it proved. Once the obvious disappointment subsides, Evans will be able to take heart from a gritty display where he continued to hang in and show flashes of his quality.
The 30-year-old from Birmingham admits clay is not his favourite surface and, with Nishikori not quite in peak condition, it transpired to be an engaging and unpredictable battle between the pair.
Evans initially looked more comfortable in the drizzle, allowing him to make the quicker start in a 29-minute opening set.
With the event taking place in autumn rather than its usual spot in May-June, the vastly different conditions have been a big talking point going into the tournament.
Both Evans and Nishikori were wrapped up in hoodies and long sleeves during the warm-up, with the Japanese player continuing to look cold in an uninspired first-set display where he won just 12 points.
However, the match swung back in Nishikori's favour in a second set which mirrored the opener and then Evans had to battle to force a tie-breaker in a third lasting almost an hour and a half.
That momentum continued in his favour as Nishikori's level dropped again in the fourth and it led to a decider that nobody would have dared predict.
Nishikori, though, has a remarkable winning record in five-set matches - standing at 23-6 coming into this one. And, after surviving an Evans fightback from 3-0 down, again showed his steeliness to come through the decisive moments.
Trailing 30-0 at 5-4, Nishikori remained focused and increased the intensity to break Evans' serve to clinch victory in three hours and 49 minutes.