Nowadays, even though the pain from last year's torn tendon in his right wrist is no longer there, the strokes and, most disconcertingly, the wherewithal, are not what they once were, to the extent that his first-round exit at the French Open on Sunday was his 10th consecutive loss.
The situation has become dire enough that Thiem, a 28-year-old Austrian once ranked No. 3 but now No. 194, acknowledged after being beaten 6-3, 6-2, 6-4 by Hugo Dellien that perhaps it's time for him to head to the lower-level Challenger Tour to get a win and gain some confidence.
After lamenting his forehand, his backhand and a too-low first-serve percentage, Thiem got to the bigger issue: ``Sometimes, I do really stupid decisions during the rally, drop shots or down-the-line (groundstrokes) at the wrong moment. (In) match match situations, I'm not playing well. ... Then, for example, there was one game today where I did four or five forehand return mistakes in a row, where I'm thinking, `What the heck is happening?'''
His quick departure was not the only noteworthy development on a cloudy, occasionally drizzly Day 1 at the year's second major tennis tournament, which welcomed back pre-pandemic sights and sounds of full attendance and no masks in the stands.
Carlos Alcaraz, the 19-year-old from Spain who is seeded No. 6 and a popular pick to win his first Grand Slam trophy, advanced just as cleanly and quickly as expected against ``lucky loser'' Juan Ignacio Londero 6-4, 6-2, 6-0 in the day's last match at Court Philippe Chatrier. Another teen, 18-year-old American Coco Gauff, also moved on, beating Canadian qualifier Rebecca Marino 7-5, 6-0.
Given Thiem's troubles _ sure, he was the runner-up to Rafael Nadal in Paris in 2018 and 2019, and to Novak Djokovic at the Australian Open in 2020, but his last victory came in May 2021 _ there were other results that probably were more surprising.
Chiefly in that category would be No. 6 seed Ons Jabeur's 3-6, 7-6 (4), 7-5 loss to 56th-ranked Magda Linette of Poland.
Jabeur, a Tunisian who is the first Arab woman to win a WTA title and first to reach a Grand Slam quarterfinal, acknowledged: ``I was expecting myself to go far in this tournament.``
As were others. That's because Jabeur began the day with a tour-leading 17 wins on clay this season, including taking the title at the Madrid Open and reaching the final of the Italian Open.
Another top-10 women's seed _ and the 2016 champion at the place _ was sent home when Garbine Muguruza was defeated 2-6, 6-3, 6-4 by 46th-ranked Kaia Kanepi of Estonia. Muguruza beat Serena Williams in the final at Roland Garros six years ago and Venus Williams in the final at Wimbledon in 2017, but she now has lost her opening match in Paris two straight years.
Avoiding that sort of result was the men's No. 9 seed, Felix Auger-Aliassime, who took care of two missing items on his resume in one afternoon: He picked up a French Open victory for the first time in three tries and he won a match after dropping the opening two sets.
The 20-year-old Canadian came back to eliminate Juan Pablo Varillas, a qualifier from Peru making his Grand Slam debut, by a score of 2-6, 2-6, 6-1, 6-3, 6-3.
Other winners included 2017 U.S. Open champion and 2018 French Open runner-up Sloane Stephens, No. 23 Jil Teichmann and No. 26 Sorana Cirstea among the women; No. 3 Alexander Zverev, No. 18 Grigor Dimitrov, No. 23 John Isner and No. 26 Botic Van de Zandschulp among the men.
Dellien, a Bolivian ranked 87th, entered his contest against Thiem with a 2-7 career record in Grand Slam matches. But from the get-go, he was able to hold his own in lengthy baseline exchanges.
On the very first point, which lasted 24 strokes, Thiem landed a backhand passing shot in the net and shook his head. On the next, he tried a drop shot that floated wide. Not really close at all. Again, a head shake. On the sixth point, a forehand return sailed well long. That initial set ended with Thiem putting a forehand into the net, followed by a backhand into the net.
``Today, he wasn't at his top level of the past, but I still needed to beat him,`` Dellien said. ``It's an important step in my career.''
(For more sports news and updates, follow Ahram Online Sports on Twitter at @AO_Sports and on Facebook at AhramOnlineSports.)