The British number one has still yet to win a main draw match at Roland Garros after bowing out meekly to Yulia Putintseva, the world number 93.
It was another hugely disappointing performance from Konta, who pre-tournament had insisted she has the game to be a success on clay.
An unforced error count of 32 suggested otherwise as Putintseva ran out an ultimately comfortable 6-4 6-3 winner.
The 23-year-old from Kazakhstan joins the similarly unheralded Julia Gorges and, from last year, the then world number 109 Hsieh Su-wei in sending Konta crashing at the first hurdle.
Putintseva can be a feisty, chuntering player who gets under her opponent’s skin, but she did not need to resort to any such antics to knock Konta out of her stride. Konta had won the first 10 points on her own serve, albeit while getting little change from Putintseva’s.
But having fended off break points at 3-3 Konta’s serve then failed her twice, crucially to gift Putintseva the first set.
Breaks were shared at the start of the second but that was as good as it got for Konta.
When she failed to put away a routine smash and two shots later saw the ball flash past her for a crucial break at 3-1, she knew her Paris hopes were all but over for another year.
Putintseva duly served out for the match to condemn Konta to another early departure.
Jelena Ostapenko’s reign as champion came crashing to a halt in the first round.
The Latvian, who was unseeded when she roared through the draw to claim her shock triumph last year, was beaten in straight sets by Ukrainian Kateryna Kozlova.
Ostapenko, seeded five, looked a shadow of the player on the Court Philippe Chatrier upon which she shone so brightly 12 months ago. She contributed 13 double faults amid 48 unforced errors to tumble out 7-5 6-3 to the world number 66.
Venus Williams was also sent spinning out on the opening Sunday.
The ninth seed, runner-up in Paris in 2002, was beaten 6-4 7-5 by Wang Qiang of China on Court Suzanne Lenglen.
Wang, ranked 85, had lost to Williams in the first round in Paris last year and also at Wimbledon a few weeks later.
But she gained revenge in spectacular style with a first victory over the seven-time grand slam winner for the biggest win of her career.
“I think she just played well,” said Williams. “I mean, all the times we’ve played, she’s played great. I think her game just got better and better during the match.”
Fourth seed Elina Svitolina recovered from 5-1 down, saving a set point, to blow away Ajla Tomljanovic of Australia.
The Ukrainian won eight games in a row – frustrated Tomljanovic’s racket was an early Roland Garros casualty – on her way to a 7-5 6-3 victory.
US Open champion Sloane Stephens was clearly in a hurry, dropping just two games in a 6-2 6-0 win over Arantxa Rus of Holland.
In the men’s draw, Grigor Dimitrov found himself facing an unexpected opponent but still got his French Open bid off to a solid start with a straight-sets win.
The fourth seed opened proceedings on Court Philippe Chatrier as he began his latest attempt to win a maiden grand slam.
After Viktor Troicki’s late withdrawal through injury, lucky loser Mohamed Safwat was only informed he was Dimitrov’s new opponent an hour before the match was due to commence.
The world number 182 from Egypt looked out of his depth in the first set but eventually found his feet, although he could not stop Bulgarian Dimitrov running out a 6-1 6-4 7-6 (7/1) winner.
Second seed Alexander Zverev wasted little time joining Dimitrov in round two. The highly-fancied German, 21, breezed past Ricardas Berankis of Lithuania 6-1 6-1 6-2 in just over an hour.
Former semi-finalist Gael Monfils shrugged off a typically sluggish first set to triumph against fellow Frenchman Elliot Benchetrit 3-6 6-1 6-2 6-1.
Another home hope, 15th seed Lucas Pouille, beat Russia’s Daniil Medvedev 6-2 6-3 6-4.
Japan’s Kei Nishori, seeded 19th, was also a straight-sets winner over Maxime Janvier of France.