Dominic Thiem looked a shadow of the player who once appeared destined to eventually rule at Roland Garros as he bowed out in straight sets in the first round of the French Open.

The former world number three, a finalist here in 2018 and 2019 when he was the latest heir apparent to serial winner Rafael Nadal, has yet to win a match since returning from the wrist injury which ended his season last year.

Thiem, easily beaten 6-3 6-2 6-4 by the unheralded Hugo Dellien of Bolivia, admits he may now consider dropping down to the second-tier Challenger Tour in a bid to rediscover how to win.

"It was not a good match at all, but it is what it is," said the 28-year-old Austrian.

"I knew that it was going to take time, that the level is extremely high from all the players competing here and I'm not there yet. I was really working hard to get there but the time was just not enough.

"I have to accept it and even though it was a really painful defeat now, week after week, it's still nothing unexpected. If I had won many matches or whatever, would have been a big surprise. So it’s painful, I’m very disappointed, but it goes on.

"Yeah, I’m definitely thinking to go back to Challenger level now for maybe one or two tournaments. Of course a match win would help a lot, but if I’m honest to myself, I was, in all the matches I played, still pretty far away from a win.

"So I’m not really thinking about it, I just have to improve and then hopefully it goes from itself and then the first match victory is coming, and then things are also working much better match-specific."

The current king of clay in-waiting, teenage sensation Carlos Alcaraz, raced into the second round showing glimpses of why he is so highly-regarded.

The 19-year-old Spaniard, who beat Nadal, Novak Djokovic and Alexander Zverev on the red dirt to win in Madrid earlier this month, swept past Juan Ignacio Londero of Argentina 6-4 6-2 6-0.

Zverev, the German world number three and highest ranked player competing on the opening Sunday, booked his place in round two with a 6-2 6-4 6-4 victory over Austrian Sebastian Ofner.

Ninth seed Felix Auger-Aliassime, of Canada, found himself two sets down to Peruvian qualifier Juan Pablo Varillas but hit back to win 2-6 2-6 6-1 6-3 6-3.