World No 4 Del Potro is still sidelined with a right knee injury sustained in Shanghai last month.
Sweden's Robin Soderling will replace Andy Roddick in the ATP World Tour finals after the American pulled out with a knee injury on Tuesday.
It was third time lucky for Tsitsipas who had twice lost in the Dubai final, against Roger Federer in 2019 and Novak Djokovic a year later.
Six-time champion Novak Djokovic has withdrawn from this year's Italian Open, organisers said on Tuesday.
A few days after it appeared as though a Roger Federer impersonator had gatecrashed the 02 Arena, the Swiss great resumed normal service to outplay Kevin Anderson and reach the last four of the ATP Finals on Thursday.
Djokovic to face World number 204 Valentin Vacherot next.
Carlos Alcaraz has defended his decision to play in the lucrative Six Kings Slam exhibition event in Saudi Arabia
Novak Djokovic moved to the brink of his 100th tour-level title after recovering from a second-set blip to beat British qualifier Cameron Norrie 6-4, 6-7(6), 6-1 in the Geneva Open semi-finals on Friday.
Belgian third seed Elise Mertens dug deep to save 11 match points and battle past two-time winner Ekaterina Alexandrova to reach the Libema Open final.
Eighth seed Machac, who won gold in mixed doubles at the Paris Olympics, became the third player from his country to win an ATP 500 title, following Tomas Berdych and Radek Stepanek.
Yuki Bhambri and his American partner Robert Galloway lost to fourth seeded combine of Francisco Cabral from Portugal and Lucas Miedler from Austria in the final.
The 19-year-old Czech Jakub Mensik beat his childhood idol Novak Djokovic in the Miami Open final in an upset for the ages on Sunday.
Rafael Nadal's decision to end his season early means Cilic is actually holding the last berth for the eight-man showdown at London's O2 Arena.
Factbox on Italy's Jannik Sinner, who beat Germany's Alexander Zverev 6-3, 7-6(4), 6-3 in the Australian Open final
Mboko saved a match point against Kazakh ninth seed Rybakina in front of adoring home support
Sumit Nagal registered a straight-sets win over Argentine qualifier Nicolas Kicker.
Arjun Kadhe and Vijay Sundar Prashanth were beaten in the semi-finals of the Swiss Open after losing in straight sets to third seeds Albano Olivetti and Hendrik Jebens.
World number two Carlos Alcaraz beat seventh seed Arthur Fils 6-2, 6-4 on Saturday to advance into his third Barcelona Open final, where the Spaniard will face Denmark's Holger Rune for the title.
Top seed Carlos Alcaraz of Spain and No. 8 seed Hubert Hurkacz of Poland will clash in the ABN Amro Open semi-finals on Saturday after both posted victories on Friday in Rotterdam, Netherlands.
While Jannik Sinner and French Open champion Carlos Alcaraz have won the last seven major titles between them, the Italian cautioned against complacency and pointed to the strength of competition in the ATP Tour.
The tournament's once-robust pool of around 300 line judges has been cut to 80 and they will serve as "match assistants", who support chair umpires and step in should the ELC -- powered by more than 450 cameras -- fail in any of the 18 courts in use.
The fourth-seeded Indo-Canadian pair got the better of second seeds Jean-Julien Rojer of the Netherlands and Romania's Horea Tecau 4-6, 7-6(9), 11-9 in a close semi-final.
Medvedev outlasts Zverev to reach Halle final
Rafael Nadal says he could miss the season-ending ATP World Tour Finals next month because of appendicitis.
Jeevan Nedunchezhiyan and his partner Vijay Sundar Prashanth clinched their maiden ATP title together, winning the Hangzhou Open men's doubles event, while Yuki Bhambri and his French partner Albano Olivetti finished runners-up at the Chengdu Open
This milestone underscores his longevity and commitment to the sport, especially considering the physical and mental demands of playing at the top level.
'It's a different surface and I've not had much time to get used to this tournament so my expectations aren't that high.'
Rajeshwaran shown the door at Mumbai Open
France's Boisson wins first WTA title in Hamburg
Jannik Sinner's dazzling winning streak ground to a halt ahead of the French Open but the world number one's top-notch return from a three-month doping ban suggests he will be the main challenger to Carlos Alcaraz in Paris.
Jannik and Carlos are the favourites at Flushing Meadows, but don't write these men off!
Skipping hard-court tune-ups in Toronto and Cincinnati, Djokovic has placed all his chips on New York in what many see as his last realistic shot at Grand Slam glory.
Mahesh Bhupathi entered his first final of this season. He and French partner Michael Llodra overcame a strong challenge from India's Rohan Bopanna and Rajeev Ram of the United States in the semi-finals of the Dubai Tennis Championships on Friday.
World number one Jannik Sinner produced a sublime semi-final display as he fought back from a set down to beat American Tommy Paul 1-6, 6-0, 6-3 on Friday to set up an Italian Open final showdown with Carlos Alcaraz.
Players from the Philippines and Hong Kong will be on the schedule for the second round of a Grand Slam for the first time this week, as the U.S. Open sees the impact of an increasingly global game.
The 21-year-old German upstart produced some dazzling tennis and thoroughly deserved his 7-5, 7-6 (5) win against the six-time champion in a captivating semi-final.
Defending champions Italy moved into the Davis Cup final after a 2-0 win over Australia on Saturday as Jannik Sinner defeated Alex de Minaur in straight sets to follow up Matteo Berrettini's victory over Thanasi Kokkinakis.
The US Open announced $90 million in prize money will be on offer at this year's final major, marking the largest purse in tennis history, up 20 percent from 2024.
Alexander Zverev rallied from a set down to beat defending champion Alexei Popyrin in Toronto and move into the semi-finals.
Factbox on Spanish second seed Carlos Alcaraz, who beat Italian world number one Jannik Sinner 4-6, 6-7(4), 6-4, 7-6(3), 7-6(10-2) in the French Open final on Sunday to win his fifth Grand Slam title.