Top-seeded Djokovic lost four straight games and had to save a set point before beating Filip Krajinovic 7-6 (6), 6-3 in an all-Serbian match, and No. 2 Thiem nearly squandered a 5-1 lead in his 6-4, 7-5 win over Vitaliy Sachko of Ukraine.
The 33-year-old Serb has been the top-ranked player at the end of a season five times: in 2011, 2012, 2014, 2015 and 2018.
French Open 2020: 'Both gave everything' Diego Schwartzman tops Dominic Thiem in gruelling five setter
Two points from defeat against the US Open champion and two-time runner-up at Roland Garros Thiem, Schwartzman found his way and emerged with a 7-6 (1), 5-7, 6-7 (6), 7-6 (5), 6-2 victory
Victory for the 12-time champion could set up another Paris clash with Dominic Thiem who he has defeated in the last two finals.
Fourteen years after Hawk-Eye made its debut at the majors at the 2006 US Open, French Open still relies on the keen eyesight of line judges and chair umpires to spot marks left by balls in the often well-trampled red clay
French Open 2020: Rafael Nadal, Dominic Thiem, Simona Halep enter last 16 as Stan Wawrinks suffers shock loss
The 12-time Roland Garros champion dispatched Italian world number 74 Stefano Travaglia 6-1, 6-4, 6-0 in just 95 minutes, notching his 96th victory at the tournament.
Thiem, 27, captured his maiden Slam in New York against Alexander Zverev, the first major final in six years not to feature at least one of the 'Big Three'. However, US broadcaster ESPN said that ratings for that championship match were down 48%.
French Open 2020: Record-chasing Rafael Nadal eases into second round; Serena Williams overcomes patchy start
Nadal needs one more Slam to match Roger Federer's record but has described the defence of his Roland Garros crown as the "most difficult ever" given the cold and damp conditions of a tournament delayed four months by the coronavirus pandemic.
French Open 2020: Rafael Nadal begins 'most difficult' campaign; Serena Williams eyes elusive 24th Major
Nadal, the undisputed king of clay, needs one more Major to equal Roger Federer's record of 20, but the Spaniard comes to Paris short of preparation and unhappy with the French Open's choice of new balls.
French Open 2020 will be daunting given little preparation, colder conditions and quick turnaround from US Open
An unusual season's final Grand Slam gets underway today at Roland Garros. There is little similar to previous French Open events with little preparation, quick turnaround, colder conditions, roof and floodlights on Parisian red dirt.
Should world number one, and 2016 champion, Novak Djokovic, or 12-time winner Rafael Nadal unexpectedly falter, it is Thiem who is most likely to benefit.
Rafael Nadal seeks his 13th French Open title, to go level with Roger Federer on 20 Slams, but little preparation and different conditions don't go in his favour.
French Open 2020: Rescheduled Grand Slam to witness colder conditions, retractable roof and much-smaller crowds
French Tennis Federation expected the worst of the coronavirus pandemic to subside by the rescheduled September date. But they face multitude of challenges ahead.
Rafael Nadal, who is seeded second, is aiming to equal the absent Roger Federer's men's record of 20 Grand Slam titles.
US Open 2020: Fourth time's the charm for Dominic Thiem, Naomi Osaka builds on and off the court, and more talking points
US Open 2020 crowned a first-time champion in Dominic Thiem and a third Grand Slam winner in Naomi Osaka in the bubble in New York.
US Open 2020: 'I will be a Grand Slam champion', Alexander Zverev vows to bounce back after loss to Dominic Thiem
The 23-year-old German went two sets and a break up in his first Grand Slam final before losing in five sets to Austria's Dominic Thiem.
US Open 2020: Dominic Thiem hopes to play more freely in future after securing career's first grand slam win
The second seeded Austrian thought he was heading for a fourth defeat in Grand Slam finals after going two sets down to fifth seeded German Alexander Zverev at Flushing Meadows.
US Open 2020: Dominic Thiem becomes first man to overturn two set deficit in 71 years at American Grand Slam, and more stats
Dominic Thiem vs Alexander Zverev at the US Open was decided by a fifth-set tiebreaker, something that had never happened in the final.
US Open 2020: Dominic Thiem beats Alexander Zverev in marathon five-setter to claim first Grand Slam title
The title marks Thiem's maiden Grand Slam trophy after three previous defeats in finals of tennis majors.
US Open 2020, Men's Singles Final, Match Highlights: Dominic Thiem beats Alexander Zverev to claim first Grand Slam title
Catch all the latest updates, live scores and more from the US Open Men's Singles final between Alexander Zverev and Dominic Thiem on Firstpost.com's live blog!