Alexander Zverev said the turning point in the four-hour thriller came when Thiem broke his serve for the first time in the third set, a break which reversed the momentum of the match.
With Nadal and Federer both skipping the tournament, Djokovic's sensational exit on Sunday after hitting a line judge in the throat with a ball opened up the field for a younger cohort of players.
Daniil Medvedev continued his march towards a first Grand Slam title on Wednesday, powering into the US Open semi-finals with a clinical 7-6(6), 6-3, 7-6(5) victory over childhood friend Andrey Rublev.
Gauff will not compete in the Tokyo Olympics after testing positive for COVID-19,
Thiem 'bagaled' Nadal at the US Open -- his first bagel set in 14 years and just his fourth ever 'bagel' set at the Slams -- to claim the first set, but the relentless matador from Spain fought back to claw his way into the match and script a 0-6, 6-4, 7-5, 6-7 (4/7), 7-6 (7/5) to reach the semi-finals for the seventh time.
Thiem became the first Austrian since Thomas Muster in 1996 to reach the final of the claycourt tournament after subduing Murray for the first time in his career.
Experienced Indian Rohan Bopanna and his Canadian partner Denis Shapovalo advanced to the second round of the US Open men's doubles event after a straight-set win in New York.
Second seed Daniil Medvedev will launch his bid to win his first major title against veteran Frenchman Richard Gasquet.
Second seed Dominic Thiem edged a first-set tiebreak before turning up the heat to romp into the US Open quarter-finals with a resounding 7-6(4), 6-1, 6-1 victory over Canadian youngster Felix Augur-Aliassime at Arthur Ashe Stadium on Monday.
Rafael Nadal shrugged off his derailed bid for the Grand Slam record with a pledge to keep "fighting" but the Spaniard leaves the Australian Open with familiar regrets after bowing out to a rising talent on Wednesday.
Dominic Thiem will take on Germany's Alexander Zverev in Sunday's US Open final.
The fifth seeded German did not let up and another break confirmed the win in two hours and 40 minutes.
Holger Rune crashed out to Yoshihito Nishioka in the ATP 250 Adelaide International 1 first round.
Rafael Nadal gets the opportunity to avenge his only defeat in 10 meetings with Diego Schwartzman, which he suffered a little over two weeks ago, when Spain's 12-time French Open winner faces the Argentine in the semi-finals at Roland Garros on Friday.
'I'm so humbled by the continuous support from my fans in Rome and I look forward to making my return soon.'
Novak Djokovic kicked off his season in style with a 7-5, 7-5 win over Canadian talent Denis Shapovalov on his favourite Rod Laver Arena court on Tuesday before returning to lead Serbia to a doubles victory that sealed their ATP Cup opener 2-1.
Bopanna and Shapovalov will take on Dutch-Romanian combination of Jeal-Julien Rojer and Horia Tecau in the quarterfinals.
Factbox on Daniil Medvedev, who defeated world number one Novak Djokovic 6-4, 6-4, 6-4 in the US Open final on Sunday to win his first Grand Slam title.
Djokovic's father blamed the cancellation of the tour on Dimitrov. There is nothing to suggest that Dimitrov spread the virus to others.
Novak Djokovic has pulled out of the Serbia team for the ATP Cup in Sydney, event organisers said on Wednesday, raising further doubts over whether the world number one will defend his Australian Open title next month.
'It's such an honour to win this tournament, looking at all the names who have won it I'm very happy and proud that my name is also there now'
World number one Rafael Nadal begins his French Open title defence, on Monday, with a clash against Italy's Simone Bolelli on Court Philippe-Chatrier.
How sweet it is: Eubanks's climb up the ranks is 'icing on the cake'
Beaten twice by Nadal in the space of a month, in the Barcelona and Madrid Open finals, Thiem took his revenge by handing the 30-year-old Spaniard a first clay court defeat of the season in Rome.
This year's French Open welcomes up to 5,388 spectators
Thirteen-time champion Rafael Nadal, 20-time Grand Slam winner Roger Federer and world number one Novak Djokovic were placed in the same half of the French Open draw on Thursday.
Tennis is like "riding a bike" for Federer, who is not worried about his game or starting with "really low" expectations, but is more interested to see how his knee reacts to the rigours of competitive tennis.
Austria's Dominic Thiem strained every sinew trying to cling on to the 32-year-old Spaniard and at times even gained a precarious foothold in his first Grand Slam final. But it ultimately proved a futile mission as, just like in all but two of Nadal's previous 87 matches here, the relentless Spaniard proved insurmountable, winning 6-4, 6-3, 6-2.
Austrian Dominic Thiem became the first player to capture titles on three different surfaces this year when he finished off Philipp Kohlschreiber to win the Mercedes Cup in Stuttgart on Monday.
Novak Djokovic endured a fierce challenge to his Melbourne Park reign before overhauling Dominic Thiem 6-4, 4-6, 2-6, 6-3, 6-4 on Sunday to clinch an eighth Australian Open crown and reclaim the world number one ranking. He captured the decisive break in the third game of the final set, then held firm as Thiem made desperate assaults on his serve. Going for broke in a nerve-shredding final game, the fifth seeded Austrian went for the lines but missed twice to hand Djokovic one of his most hard-earnt triumphs.
Belgian Goffin, thrashed by Grigor Dimitrov two days ago, appeared to be feeling the effects of that mauling as he went 3-0 down with a whimper, but came alive to win 15 points in a row during a first-set comeback.
German seventh seed Alexander Zverev recovered from a slow start to beat former champion Stan Wawrinka 1-6, 6-3, 6-4, 6-2 in the Australian Open on Wednesday to reach his first career Grand Slam semi-final. Swiss Wawrinka, who won the first of his three Grand Slams at Melbourne Park in 2014, broke Zverev twice early in the opening set to breeze through the opening set but the 22-year-old German came roaring back into the contest.
Six-time Australian Open champion Djokovic pulled out of a tournament in Abu Dhabi last week because of continuing problems with his right elbow and wore a sleeve over the joint during his round robin match against the Austrian.
Former champions Novak Djokovic, Rafael Nadal and Serena Williams have all entered next month's Western & Southern Open in New York, which will serve as a tune-up for the US Open, tournament organisers said on Wednesday. Organisers of the August 20-28 event, which was relocated from Cincinnati this year because of COVID-19, said defending champions Daniil Medvedev and Madison Keys are also among the initial entries.
Defending champion Rafael Nadal thrashed Austrian fifth seed Dominic Thiem 6-0, 6-2 to reach the semi-finals of the Monte Carlo Masters for a record 14th time on Friday.
Nadal was leading the match 6-1, 2-0 when Correno Busta decided he had had enough.
Roger Federer's struggles continued when he was beaten 7-6 (2), 6-4 by fast-rising Austrian Dominic Thiem in the third round of the Italian Open in Rome, on Thursday.
Nadal's great rival and fellow 20-times Grand Slam winner Roger Federer is also out of the US Open and will be sidelined for many months because he needs knee surgery.
Thiem blazed 50 winners, many of them jaw-dropping backhands, to beat Djokovic