The reigning US Open champion produced his best tennis during the match’s biggest points, saving break points and set points to qualify for Sunday’s final.
Both players were evenly matched in the opening set until Thiem got the first break of the match late into the first set which eventually proved decisive.
The pair played out a mammoth second set tie break, with both struggling to hit the winning shot, before Djokovic eventually managed to edge it.
In the decisive third set, once again they couldn’t be separated, and Thiem produced a remarkable comeback in the third set tie break, coming from 4-0 down to eventually win and advance to the final in London for the second year in a row.
“It was for sure a mental battle,” Thiem said afterward.
“I mean, I got so tight in the second set tie break, first of all because to play these legends is always going to be something special and playing for a final at the ATP Finals is also something very special. I thought after my first big title in New York, I’m going to be a little bit more calm but that was a mistake, I guess,” Thiem said.
“I was just as tight and just as nervous as before. And it was so much on the edge, that match, like every single match here where the best players in the world are facing off. So I’m just incredibly happy to be through and just try to get ready for tomorrow.”
Not much to separate them
In a cagey opening set, each player held on to their services games until very late, with their powerful serves and excellent ground games proving too much for each other.
The tension proved all too much for Thiem at one point as, after losing a game to give Djokovic the lead in the opening set, he tossed his racket off the court into the stands in apparent frustration.
The decisive break came in the 11th game of the tight set, as Thiem eventually edged a Djokovic service game to make the score 6-5. He held on to his following service game to win the opening set and move within a set of a place in the final.
After the short break for the players to catch their breath and take on some nutrients, the second set began in a similar vein, with both players holding serve.
Djokovic, looking stronger as the match progressed, failed to capitalize on any of the break points he crafted for himself, as the second set continued all level.
And as he had done all match, Thiem stepped up during the biggest points of the game, saving two set points in his final service game to take the second set to a tie break.
As was becoming clear, both players struggled to be separated in the tie break. Djokovic raced into a 4-2 lead before Thiem roared back, only for Djokovic to save two match points shortly after.
The pair continued to prevent each other winning the second set, saving match points and set points, before Djokovic clinched the set-winning point as Thiem’s backhand return could only find the net.
In the all-important third set, it was more of the same. Both players held serve as they struggled to break down one another, needing a tie break to decide them once more.
Having raced into a 4-0 lead, Djokovic failed to stop Thiem recovering to level the tie break before the Austrian eventually took the lead.
Djokovic saved one match point but could not save the second as Thiem advanced to the final.
Thiem will face either Daniil Medvedev or Rafael Nadal in the final on Sunday. Medvedev and Nadal play later Saturday.