Later Saturday in the women's final, Ashleigh Barty defeated Marketa Vondrousova, an unseeded 19-year-old from the Czech Republic, in straight sets, 6-1, 6-3. Barty, the 23-year-old eighth seed, became the first Australian to capture the French title since Margaret Court in 1973.
Thiem will face two-time defending champion Rafael Nadal in the final Sunday in Paris. Nadal, who beat Roger Federer 6-3, 6-4, 6-2 in the semifinals Friday, defeated Thiem in straight sets last year for his 11th French Open title.
"He is the favorite, of course," Thiem said of Nadal. "I'm really looking forward to tomorrow, to let everything out on the court again. We'll see."
Thiem led Djokovic 6-2, 3-6, 3-1 when play was stopped Friday. Resuming play just after 6:15 a.m. EDT, Thiem took an aggressive approach and focused on hitting the lines to finish the third set.
Hoping to capture his fourth consecutive Grand Slam title, Djokovic cruised in the fourth set. Rain forced a weather delay in the final set and kept both players off the court for just over an hour.
TV cameras caught a heated Djokovic screaming at officials, although he was not awarded a penalty for verbal abuse. Djokovic, who won the French Open in 2016, also stopped play in the fifth set to contest a ball he thought was out.
"Obviously when you're playing in hurricane kind of conditions, it's hard to perform your best," Djokovic told reporters. "It's really just kind of surviving in these kind of conditions and trying to hold your serve."
The two battled back and forth in the final set before Thiem clinched the victory.
"He showed why he's one of the best players in the world," Djokovic said.
The men's match, including the rain delay, delayed the start of the women's final by 1 1/2 hours.
Neither Barty nor Vondrousova had been in a Grand Slam-event semifinal until this week, either.
"I played the perfect match today," Barty said.
Barty won the Wimbledon girls title at age 15. But four years ago she decided to play professional cricket in Australia before returning to tennis in 2016.
"It's just been a crazy two weeks," Barty told the crowd.
Barta took a 4-0 lead in the first set.
The 38th-ranked Vondrousova hadn't dropped a set before the final.