The former world number three has not played on the ATP Tour since damaging his wrist in Mallorca last June but was due to face Tomas Martin Etcheverry or Nicolas Jarry in Argentina.
However, the 2020 US Open champion confirmed on Monday: "In the last days, I suffered a minor injury between my knuckles, a little strain of my ligament.
"The positive thing is the wrist is perfectly fine, but I'm suffering pain in my hand and also lacking practice, so I have to pull out.
"I'm very sad, but I'm going to come back once I'm 100 per cent fit, and thank you so much for the great and warm welcome I had here in Cordoba."
Thiem's withdrawal makes for a potentially simpler quarter-final draw for Pedro Martinez, who came through a marathon contest on Monday against Thiago Monteiro.
The eighth seed, who will next face Juan Ignacio Londero, won 4-6 6-4 7-6 (7-4) in a match lasting just under three hours.
There was an even longer battle between Juan Pablo Varillas and home favourite Facundo Bagnis, who was defeated 6-4 5-7 7-6 (7-5) after three hours and 17 minutes on court. Varillas will play Albert Ramos-Vinolas or Andrej Martin in the next round.
Jaume Munar also sealed his progress, defeating Benoit Paire in straight sets.
Thiem, playing his first tournament since reaching the Australian Open final, was pushed by Jaume Munar before winning 6-7 (5-7) 6-3 6-4 on the clay in Brazil.
The Austrian top seed, who won the ATP 500 event in 2017, needed two hours, 41 minutes to advance, having also dropped a set in his opener.
Thiem will face Gianluca Mager in the quarter-finals after the Italian qualifier's 6-3 7-6 (7-5) victory over Joao Domingues.
Borna Coric moved into the last eight courtesy of a 6-3 1-6 7-6 (7-5) win against wildcard Thiago Seyboth Wild.
The fifth seed will meet Lorenzo Sonego, who upset second seed Dusan Lajovic 7-6 (7-5) 7-6 (7-5).
At the Delray Beach Open, Raonic – the 2017 runner-up – served 11 aces in a 7-5 6-3 win over Cedrik-Marcel Stebe that sent him into the quarter-finals.
Steve Johnson awaits the Canadian after overcoming 2017 champion Jack Sock 6-4 5-7 6-1.
Frances Tiafoe, the 2018 winner, and Ugo Humbert set up a last-eight meeting with straight-sets victories over Tommy Paul and Miomir Kecmanovic respectively.
Thiem missed the second half of last season due to a wrist injury and has won only one set in six matches since returning at an ATP Challenger Tour event in Marbella in March.
The 2020 US Open champion's latest loss came at the hands of Marco Cecchinato, who prevailed 6-3 6-4 to reach the second round on Monday.
A two-time runner-up at Roland Garros, Austrian Thiem will travel to Paris struggling to return to form following such a long absence.
Cecchinato had lost all 11 matches this year, but has won three in Geneva without losing a set after coming through qualifying and will now face Kamil Majchrzak.
Federico Delbonis, the seventh seed, beat Ricardas Berankis 6-4 6-4, while French duo Richard Gasquet and Benoit Paire made it through to the last 16 along with Ilya Ivashka.
There will be no fairytale win for Jo-Wilfried Tsonga, who will retire after the French Open, at the Lyon Open after he suffered a 6-4 6-4 loss to Alex Molcan.
Eighth seed Pedro Martinez was knocked out by Yosuke Watanuki in the first round, but Karen Khachanov beat Gilles Simon 6-1 6-4 and Lucas Pouille was also beaten in his homeland, falling to Oscar Otte.
Thiem showed signs of returning to his best with runs to the last eight or better in three tournaments in July, but the 2020 US Open winner was in danger of falling at the first hurdle in North Carolina when he lost the first set against the American wildcard.
But Thiem, a debutant in the competition, bounced back, and after a long rain delay he prevailed 6-7 (5-7) 7-5 7-6 (8-6), and he will now face Dimitrov, who is seeking a first trophy since 2017.
The Austrian had to save two match points during a last-set tie-break, and said afterwards: "First of all I'm super happy to get that win, [my] first win on hard courts since a very long time, since March 2021, I guess.
"It was not easy at all today with the rain delay, coming back out there at 11:15 p.m. It was very late. I had trouble [getting] into the match again.
"But luckily I raised the level a little bit in the third-set tie-break and compared to Kitzbuhel, where similar stuff happened with the rain, the luck was on my side today."
Second seed Botic van de Zandschulp also learned of his last-32 opponent on Monday, with Tallon Griekspoor beating fellow lucky loser Taro Daniel 7-6 (7-3) 6-3.
Last year's beaten finalist Mikael Ymer ensured a safe passage through, meanwhile, thanks to a 6-2 6-3 victory against Federico Coria.
Australia's James Duckworth also advanced with a 4-6 6-3 7-5 (7-5) comeback win over compatriot Thanasi Kokkinakis, while Kyle Edmund saw off Michail Pervolarakis 6-2 7-5.
Sixth seed Nikoloz Basilashvili was a big-name exit, as he went down to Thiago Monteiro.
Thiem, a 2019 winner at the tournament in his home country, prevailed 6-4 6-2 in Kitzbuhel.
He will next face compatriot Sebastian Ofner as he seeks a first title since his grand slam breakthrough at the US Open in 2020.
Ofner came from a set down to beat former world number seven Richard Gasquet 1-6 7-5 7-5.
Meanwhile, seventh seed Pedro Martinez saved six out of six break points en route to a 7-6 6-3 victory over Chilean Nicolas Jarry.
At the Croatia Open in Umag, Bernabe Zapata Miralles set up a round of 16 meeting with third seed Holger Rune by beating Croatian Dino Prizmic, who retired when facing a 6-4 3-0 deficit.
Alex Molcan is safely through to the next round after defeating Duje Ajdukovic, while French 23-year-old Corentin Moutet cruised to a straight-sets victory over sixth seed Daniel Altmaier.
Thiem was on the brink of being knocked out by the top seed in Antwerp, but fought back to win 3-6 7-6 (11-9) 7-6 (7-4).
The 2020 US Open champion fended off all three match points in a second-set tie-break to take a thrilling quarter-final the distance and then came out on top in another breaker to advance.
Thiem will do battle with Sebastian Korda for a place in the final after the American emphatically defeated eighth seed Yoshihito Nishioka 6-0 6-2.
Richard Gasquet moved into the last four at the expense of David Goffin and will face Felix Auger-Aliassime, who came from a set down to beat Dan Evans.
Matteo Berrettini remains in the hunt to win the Tennis Napoli Cup on home soil after a 6-2 6-3 quarter-final triumph over Taro Daniel.
Top seed Pablo Carreno Busta crashed out in Italy, losing 7-5 6-2 to Miomir Kecmanovic, who will face Lorenzo Musetti after he got the better of Daniel Elahi Galan. Mackenzie McDonald will come up against Berrettini after getting past Zhang Zhizhen.
Stefanos Tsitsipas sealed a Stockholm Open semi-final spot with a 7-5 6-3 win over Mikael Ymer and will take on Emil Ruusuvuori, who eliminated Frances Tiafoe.
Holger Rune and Alex de Minaur meet in the other last-four match in the Swedish capital following wins over Cameron Norrie and Denis Shapovalov respectively.
Thiem, last in action in an Australian Open final loss to Novak Djokovic, returned with a 6-2 4-6 6-1 victory over wildcard Felipe Meligeni Alves on Tuesday.
The 2017 champion of the ATP 500 event played on clay in Brazil, top seed Thiem grabbed two breaks of serve in the deciding set.
Having started 2020 with four losses in five matches, Borna Coric found a victory by overcoming Juan Ignacio Londero 7-6 (7-5) 7-5.
Dusan Lajovic joined Thiem and Coric as the three seeds to win, but two fell in the opening round.
Casper Ruud, coming off a title win at the Argentina Open, went down to qualifier Gianluca Mager 7-6 (7-4) 7-5.
Guido Pella, the 2016 runner-up, was edged by Thiago Monteiro 5-7 6-4 7-6 (7-3) after just over three hours.
At the Delray Beach Open, Sock claimed his first non-Laver Cup singles win since late 2018.
The American 2017 champion, a wildcard, battled past last year's winner Radu Albot 3-6 6-3 7-6 (7-2), saving a match point in the final set and breaking down in tears following his victory.
Canadian second seed Milos Raonic brushed past lucky loser Denis Istomin 6-2 6-2 and Reilly Opelka served 20 aces in a 6-7 (5-7) 6-4 7-6 (7-4) victory over Ernests Gulbis.
Ugo Humbert, the French sixth seed, battled through, while third seed Taylor Fritz fell to qualifier Cameron Norrie 6-4 6-7 (4-7) 6-4.
Number two seed Thiem retired due to a wrist injury when 5-2 up in the opening set against Adrian Mannarino in the Mallorca Championships on Tuesday.
An MRI conducted at a Mallorca hospital was inconclusive, so the US Open champion will now undergo further tests.
In an update on Wednesday, Thiem wrote on social media: "Yesterday during the match I had a problem with my wrist.
"I went immediately to do an MRI at the hospital in Palma de Mallorca. The results weren't that clear and I have decided to go to Barcelona to check with a specialist.
"I hope I can get the results and a clear diagnosis in the next days."
The ATP 250 event continued without him in Mallorca, as Roberto Bautista Agut moved into the quarter-finals with a 6-3 7-5 triumph over Italian Stefano Travaglia.
More Spanish success on home soil arrived as Pablo Carreno Busta won 6-4 6-4 against Jiri Vesely.
In the doubles, Novak Djokovic and Carlos Gomez-Herrera saw off top seeds Marcel Granollers and Horacio Zeballos to reach the last four in that competition.
Djokovic appears to be enjoying himself as he continues to prepare for Wimbledon, saying: "This was a huge win for us, beating one of the best doubles players in the world after losing the first set.
"We are having a lot of fun on the court. I thought we played well even though we lost the first set."
There was a major upset at the Viking International in Eastbourne, meanwhile, with number one seed Gael Monfils suffering a shock last-16 defeat to Australia's Max Purcell – ranked number 283 in the world.
Purcell, who is only in the tournament as a lucky loser, claimed a huge 6-4 5-7 6-4 win in a battle lasting over two hours.
Monfils fired down 16 aces and fought back after being within two points of defeat in the second set but was ultimately beaten and has not made an ATP quarter-final since February 2020.
"It feels unbelievable," said Purcell. "I thought I'd come out and have a go.
"I've struggled to get into any singles events over the past nine months and primarily played doubles, so to get on a run here, on my favourite surface, is great."
Purcell will take on Andreas Seppi – a comfortable winner over Emil Ruusuvuori – in the last eight.
While Monfils crashed out, there was less drama for the second and third seeds.
Alex de Minaur won 6-3 6-4 against home hope Liam Broady, while Lorenzo Sonego was a 6-4 6-2 victor in his contest with John Millman.
Thompson overcame big-serving American Isner – who had a first-round bye – 7-6 (7-2) 6-7 (3-7) 6-3 in New York on Thursday.
Isner was playing his first match since being forced to retire from his third-round clash against Stan Wawrinka at the Australian Open due to a foot injury.
Thompson lost to Isner in last year's New York quarter-finals but the Australian turned the tables after two hours, 31 minutes.
"I'm pretty stoked about that. That was a tough match," Thompson said. "I didn't get too many looks at Isner's serve, but managed to get the one break and held onto it."
Standing in the way of Thompson and the semi-finals is Andreas Seppi.
Opelka opened his title defence by cruising past Yoshihito Nishioka 6-4 6-4 at the ATP 250 tournament.
Next up is qualifier Jason Jung, who stunned seventh seed Cameron Norrie 6-4 6-4, Kyle Edmund – the eighth seed – was too good for German Dominik Koepfer 6-2 6-4.
At the Argentina Open in Buenos Aires, Diego Schwartzman and Guido Pella moved through to the quarters on clay.
Schwartzman – the top seed – prevailed 6-3 4-6 6-2 over Federico Delbonis and second seed Guido Pella survived a marathon against Facundo Bagnis 7-6 (7-2) 6-7 (2-7) 6-4.
Fellow seeds Laslo Djere and Albert Ramos-Vinolas, however, crashed out following defeats to Juan Ignacio Londero and Pablo Cuevas.
Korda had eliminated top seed Felix Auger-Aliassime in the quarter-finals in Portugal to set up an all-American last-four clash, and looked on course to reach the final after winning the first set against Tiafoe.
However, the fifth seed roared back to seal a 4-6 7-6 (7-2) 6-4 victory and set up a final encounter with Argentina's Sebastian Baez, who beat Albert Ramos-Vinolas to reach his second tour-level final.
Baez also needed three sets in his semi-final clash after losing a competitive second-set tie-break, but he then produced a scintillating performance to win the decider without dropping a game, winning 6-3 6-7 (7-9) 6-0.
Elsewhere, Danish 19-year-old Rune sealed his first ATP tour final appearance by beating home favourite Oscar Otte 6-4 6-4 at the BMW Open in Munich.
Rune, who has enjoyed a dream week in Bavaria after sensationally downing Alexander Zverev in the last-16 and failing to drop a single set in the tournament, revealed his ambitions to become world number one in the future after the victory.
"It's a pretty unreal feeling," he said of his semi-final win. "I didn't expect this at all coming into this tournament, and I just took it match by match. Obviously, I had a tough draw, playing Zverev in the second round, but I knew it was going to be tough, so I was ready from the beginning, and I'm super happy to be in the final.
"It's getting better and better, I'm improving every day, and this is what matters. I have some goals to be number one in the world, and you have to start somewhere."
Rune will face eighth seed Botic van de Zandschulp in the final after the Dutchman rallied to beat Miomir Kecmanovic 2-6 7-6 (7-4) 6-4 in his own final-four encounter.
Wu landed a 7-6 (7-1) 6-4 win against the Canadian Davis Cup winner and former top-10 player in their second-round contest.
World number 97 Wu, who this week became China's second player to reach the ATP top 100, has surged from 1,869th on the ranking list last April and believes he can crack the top 30 by the end of the year.
Speaking after getting the better of Shapovalov, who stands at 27th in the rankings, Wu said: "I've been playing great tennis the past few months. Hopefully I can keep playing good."
Frances Tiafoe cruised into the quarter-finals with a 6-1 6-3 win over fellow American Mackenzie McDonald.
Second seed Tiafoe was playing for the first time since his third-round elimination to Karen Khachanov at the Australian Open last month.
He faced just one break point in the entire match and needed just 59 minutes to deal with the world number 59.
J.J. Wolf, seeded sixth, will face Tiafoe in the last eight after he saw off Romania's Radu Albot in a 6-3 7-6 (7-5) win.
At the Cordoba Open, fifth seed Pedro Cachin was the biggest casualty on Wednesday as he was beaten 6-3 6-4 by Bolivian qualifier Hugo Dellien.
Seventh seed Pedro Martinez was also ousted in the first round, while Bernabe Zapata Miralles was sent packing by Tomas Barrios Vera in the last 16, losing 5-7 6-4 6-3.
Fourth seed Sebastian Baez had no such issues with Italy's Luciano Darderi, however, reaching the quarter-finals as a 6-3 6-4 winner.
Persistent rain this week in Houston meant the past three days of play have not been completed forcing a massive pile-up of matches on Saturday with the conditions clearing up.
Tiafoe took on Steve Johnson in the morning, winning 6-2 6-4 in the second round, before toppling Australian sixth seed Jason Kubler 6-4 6-4 in the quarter-finals.
The American, who only had a break of two and a half hours between his two matches, said: "I haven’t played two matches in one day in a long time.
"I thought it was unbelievable how I was able to come out here and play so well."
Tiafoe will take on Dutchman Gijs Brouwer in the last four after he got past fourth seed John Isner 6-4 7-6 (7-4), before taking down fifth seed J.J. Wolf 6-3 6-4.
Second seed Tommy Paul was another fancied American to bow out on Saturday, losing 7-6 (8-6) 6-2 to German qualifier Yannick Hanfmann in the second round.
Hanfmann progressed to the semi-finals where he will face Argentinian eighth seed Tomas Martin Etcheverry, with the German getting past Czech qualifier Tomas Machac 6-2 6-1.
Machac had bundled out American seventh seed Marcos Giron 6-4 6-4 in the second round.
Etcheverry progressed with victories over Australia's Max Purcell and Chile's Cristian Garin, winning the latter 6-1 6-7 (2-7) 6-3 in more than two and a half hours.
Swiss legend Federer had been out of action for 14 months after undergoing knee surgery, but he was back in business with a 7-6 (10-8) 3-6 7-5 win over Briton Evans.
The 20-time grand slam champion had spent a lot of time practicing with Evans in recent weeks before making his comeback and they spent another two hours and 24 minutes on court in a tight tussle on Wednesday.
Federer was delighted to be back after such a lengthy absence and the 39-year-old's next test will come against Nikoloz Basilashvili in the quarter-finals in Doha.
He said: "I was tired, I was more focused on being tired than winning the points. If I was going to go out, I was going to go out swinging. Dan had more energy left at the end but I was serving well and I thought I played a really good match. I'm incredibly happy about my performance.
"It was a pleasure to share the court with Dan and always nice to finish off with a backhand down the line on match point. The important think is how I feel tomorrow and the next day and so forth for the next six months.
"It's been a long and tough road for me. I enjoyed it though, it's been a huge challenge in my tennis career."
Top seed Dominic Thiem earlier needed three sets to defeat wildcard Aslan Karatsev 6-7 (5-7) 6-3 6-2, while the in-form Andrey Rublev was given a walkover after Richard Gasquet withdrew due to a leg injury.
Denis Shapovalov beat Vasek Pospisil in an all-Canadian encounter, while Roberto Bautista Agut was among the other winners.
Karen Khachanov reached the quarter-finals of the Open 13 Provence with a 7-6 (7-4) 6-4 win over Mackenzie McDonald, while Jannik Sinner ousted Hugo Gaston in straight sets.
Cameron Norrie, Matthew Ebden and Egor Gerasimov were also victorious in Marseille.
Making his debut in Marrakech, Auger-Aliassime arrived off the back of an impressive start to 2022.
Indeed, the world number nine had already triumphed in Rotterdam and been runner-up to Andrey Rublev in Marseille.
But he came unstuck at the hands of the player ranked 56 places lower, with Molcan securing his first career win over a top-10 player.
The Slovakian crucially broke in game nine on the way to taking the opening set. Auger-Aliassime, who hit 10 double faults during the contest, responded by dominating the second, while the players exchanged breaks in a decider that went to a tie-break.
The top seed forced match point at 7-6 up, but Molcan held on by reeling off the next three to secure a dramatic victory.
David Goffin, meanwhile, claimed his 300th tour-level win as he came from behind to defeat three-time champion Pablo Andujar.
Andujar had seen off second seed Dan Evans in the first round but, despite making a fast start against Goffin, it was the Belgian who triumphed 5-7 7-6 (7-4) 6-3.
Federico Coria overcame Mirza Basic in straight sets, while Roberto Carballes Baena defeated Portugal's Joao Sousa 6-2 7-6 (7-4) and Richard Gasquet saw off Pavel Kotov.
Auger-Aliassime won just 50 per cent of points behind his first serve as Korda claimed an impressive 6-2 6-2 success over the Canadian in one hour and 29 minutes.
In the semi-finals Korda will take on fellow American Frances Tiafoe, who edged out Alejandro Davidovich Fokina 7-6 (7-5) 5-7 7-5 in a tight encounter.
The other last-four clash will see Albert Ramos Vinolas take on Sebastian Baez.
Ramos Vinolas bested Fernando Verdasco 6-2 6-2 to set up his meeting with Baez after the Argentine rallied from a set down to defeat Richard Gasquet 3-6 6-1 6-4.
At the BMW Open, second seed Ruud fell to Botic van de Zandschulp in the quarter-finals.
The Dutchman won their only previous encounter en route to the last eight at last year's US Open and he triumphed 7-5 6-1 in Munich.
"Maybe the score is easier than it really was," said Van de Zandschulp. "The first set [was] really tight, I think. A great battle in the first one. I had some opportunities to break him in the beginning and didn't take them. Gladly [at] five-all I made the break and held the serve at 6-5.
"[The] second set was a little bit easier, but I think I played really well today."
Next up for Van de Zandschulp is Miomir Kecmanovic, who defeated Nikoloz Basilashvili 7-6 (7-5) 6-2. Holger Rune will continue his impressive run against Oscar Otte in the other semi-final after they overcame Emil Ruusuvuori and Alejandro Tabilo respectively.
Top seed Carreno Busta needed an hour and 38 minutes to dispatch his fellow Spaniard 7-6 (7-2) 6-3 in Marbella on Wednesday.
Carreno Busta won 73 per cent of points on his first serve and saved the only two break points he faced to set up a quarter-final against Soonwoo Kwon, who beat Facundo Bagnis 6-1 6-3.
Albert Ramos-Vinolas was another home contender to progress, getting the better of Ricardas Berankis 6-3 4-6 6-3, while Norbert Gombos ousted eighth seed Federico Delbonis 5-7 7-6 (7-4) 7-6 (7-1).
There were no surprises in the Sardegna Open, where all three seeds in action moved into the last eight.
Taylor Fritz, the second seed, saw the back of Andrej Martin 6-2 7-6 (7-4) to set up a meeting with Aljaz Bedene, who beat Egor Gerasimov 6-4 7-6 (7-5).
Fifth seed Jan-Lennard Struff needed only 81 minutes to defeat qualifier Liam Broady 6-4 6-2, while Nikoloz Basilashvili rallied from a set – and five match points – down to see off Jozef Kovalik 4-6 6-4 7-5.
Fognini, competing for the first time since undergoing arthroscopic surgery on both ankles in May, went down 6-1 6-2 to world 303 Huesler in a little under an hour.
The 2011 French Open quarter-finalist was broken in the second game and Huesler, who had just two previous career wins on the ATP Tour, broke again in the sixth.
After saving three break points in the early stages of the third set, Huesler held serve and secured a famous win in Kitzbuhel with minimal fuss.
Feliciano Lopez awaits in the last eight after battling to a 7-5 6-7 (4-7) 7-6 (7-3) victory over seventh seed Guido Pella in three hours.
World number 14 Schwartzman triumphed 6-3 6-2, converting three of five break points to win in one hour and 10 minutes.
Schwartzman will face Colombian lucky loser Daniel Elahi Galan who progressed with a 6-2 3-6 6-1 victory over Jaume Munar.
Eighth seed Pedro Martinez was eliminated by Argentina wildcard Juan Ignacio Londero 6-3 7-6 (7-3).
Londero will face Serbian Nikola Milojevic, another lucky loser, who got past wild card Tomas Martin Etcheverry 6-3 7-6 (7-4).
Fritz, who at 25-years-old is seeking the fifth ATP singles title of his career, allowed seventh-seed Giron only one break point opportunity for the entire match. Fritz himself only created two such opportunities, and further illustrating the closely-fought nature of the battle, Fritz edged the total point count 86-85.
With the win, Fritz booked his place against China's Yibing Wu in the semi-final after the 23-year-old defeated 34-year-old French veteran Adrian Mannarino 6-3 6-4.
The other semi-final will be an all-American showdown after J.J. Wolf upset second seed Frances Tiafoe 4-6 6-3 6-4, and 37-year-old John Isner proved too much for Ecuador's Emilio Gomez in a 7-6 (10-8) 7-5 victory.
Meanwhile, Spain's Albert Ramos-Vinolas is one match away from a final in his home country after defeating Joao Sousa 6-4 2-6 6-1 in the quarter-final of the Cordoba Open.
Ramos-Vinolas will play Argentina's Federico Coria for a spot in the decider after he emerged victorious 6-3 3-0 (ret) against compatriot Francisco Cerundolo.
Heading into the quarter-finals, Francisco and his brother Juan Manuel Cerundolo were on a collision course to meet in the final, but now both are eliminated after 21-year-old Juan Manuel fell 6-7 (5-7) 6-4 6-0 to Bolivia's Hugo Dellien.
Dellien will play fourth seed Sebastian Baez in the other semi-final after eliminating Chile's Tomas Barrios Vera 6-1 3-6 6-1.
With Norrie having already set up a quarter-final against last year's runner-up Sebastian Korda, the Briton was joined in the last eight by the second and third seeds.
Grigor Dimitrov defeated Mitchell Krueger to mark his first appearance since a disappointing second-round exit at the Australian Open in style.
The Bulgarian won 7-6 (7-4) 6-3, with Serena and Venus Williams watching on from the crowd in far from ideal conditions in Florida.
"It's always very tough [in your opening match], especially playing the last match on," Dimitrov said.
"I've been here for a week already and I was eager to get out there and play. Today was just a match I had to get through. Very tough conditions: rain, wind, cold, hot. It is what it is, and you've got to deal with it."
Opelka, who won the tournament in 2020, went the distance against fellow American Jack Sock, eventually prevailing 6-7 (6-8) 7-6 (7-4) 6-1.
He will face Adrian Mannarino in the last eight, after the Frenchman's 6-4 2-6 7-5 defeat of Brandon Nakashima. Dimitrov will play Australian John Millman.
At the Rio Open, only two of the four scheduled matches were completed due to rain.
Qualifier Miomir Kecmanovic dispatched sixth seed Lorenzo Sonego 7-5 6-4, while Francisco Cerundolo overcame Roberto Carballes Baena.
Top seed Matteo Berrettini's clash with Brazilian Thiago Monteiro was pushed back to Friday, while Carlos Alcaraz will resume his match against Federico Delbonis in a strong position in the first set.
