David Goffin's withdrawal due to injury afforded Roger Federer a walkover route into his eighth Cincinnati Masters final, with Novak Djokovic awaiting him in Ohio on Sunday.
Federer, who has won all seven of the finals he has appeared in at the ATP Masters 1000 event, had taken the opening set 7-6 (7-3) and it was 1-1 in the second when 11th seed Goffin was forced to call a halt to the contest.
"David would never pull the plug unless he had to," Federer said in an on-court interview.
"I have a lot of respect for him [but] I'm excited to be in another final in Cincinnati."
Of Djokovic, Federer said: "He's been one of the toughest guys to play against in my career, no doubt about it. He's a great champion. We've had great battles over the years, including here."
The Serbian is a five-time losing finalist in Cincinnati, Federer getting the better of him in the decider in 2009, 2012 and 2015.
A tight, high-quality encounter between Federer and the world number 11 on Saturday initially flew by without a break-point opportunity being offered by either player until the penultimate game, when Goffin had to fight hard to stave off three break and set points.
Federer netted a backhand volley to give up a mini break right from the off in the resulting tie-break, but Goffin promptly gave it straight back by rushing a forehand and dragging it into the net.
A wide forehand off the next point saw the Belgian's situation worsen, and Federer took advantage, sending down his eighth ace of the set to take control, before another netted forehand rally ball saw Goffin succumb.
The 27-year-old, who had been serving below his top speed throughout the opener, then called for the trainer, with his shoulder and right arm both receiving medical attention.
And Goffin lasted just two games of the second set before he was forced to retire.
13. November 2018
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|Welbeck has successful second operation on broken ankle|
|UEFA warns FFP cases can be reopened based on ´new information´|
12. November 2018
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|WATCH: Rooney looking sharp in England training return|
|Mbappe: Money in football is truly indecent|
|Djokovic back to brilliant best as Isner is beaten|
|Celta Vigo replace Mohamed with Cardoso after Real Madrid defeat|
|Joshua intrigued by Usyk, says Hearn|
|Ibrahimovic beats Rooney to MLS Newcomer award|
|Rams WR Kupp out for season with torn ACL|
|Sturridge denies ever gambling on football following FA charge|
|Koeman understands De Ligt´s Eredivisie frustrations|
|Jimmy Butler trade: 76ers acquire Timberwolves star in blockbuster deal|
|´Improve your attitude´ - Deschamps issues Dembele warning|
|Sturridge charged with misconduct over alleged breach of betting rules|
|Saints sign Marshall following Bryant injury|
|Mendy suffers knee injury, leaves France squad with Lacazette|
|Zverev beats Cilic in error-strewn London battle|
|Rafinha replaces injured Casemiro in Brazil squad|
|´One-dimensional´ Australia batsmen need work before World Cup - Finch|
|Mancini keen to work with ´incredibly gifted´ Tonali|
|Italian manager of the year Allegri targets long Juve stay|
|Injured Lee departs as Wales prepare squad for Tonga|
|Conte content to wait until June for coaching return|
|Etzebeth set to return, Whiteley a doubt for Scotland Test|
|In-form Verstappen does not need distractions from 2019 challenge|
|FA asks Guardiola to explain Manchester derby referee comments|
|LaLiga MVP Messi hopes the division stays wide open|
|Murray and Henshaw out of All Blacks Test|
|Injured Man Utd duo Pogba and Martial drop out of France squad|
|Modric cannot always be the best - Dalic|
|Very troubling times - LeBron James alarmed by gun violence|
|Bayern confirm Ribery ´altercation´ with reporter|
|Madrid hit by injuries to Nacho and Casemiro|
|Record-breaking Mushfiqur torments Zimbabwe|
|Spartak Moscow appoint Oleg Kononov|
|Rooney predicts ´exciting time´ after being named in MLS Best XI|
|Former England call-up Graham replaces Thomson in Scotland squad|
|Slater and Thurston among Queensland greats to join Maroons staff|
|Rapana set for six months out after shoulder surgery|
|Alves determined to play in the Premier League|
|Rockets GM denies Anthony will be waived|
|Monaco´s plight not Henry´s fault - Silva|
|It´s like the FBI came - River assistant unable to talk to Gallardo during final|
|Norman says Washington home crowds ´just don´t really care´|
|Bucks beat Nuggets to finish gruelling schedule stretch|
|Madrid ´very happy´ with Solari, says Butragueno|
|Titans stun Patriots, Browns upset Falcons|
|Browns´ Chubb relishes record-breaking performance: It definitely is very special|
|MLS Review: Red Bulls, Atlanta to meet in conference finals|
|Neymar wants more from perfect PSG|
|Higuain is feeling a lot of pressure – Gattuso|
|I didn´t insult anyone, says apologetic Higuain|
|Allegri delighted with Juventus response|
|Kyle Busch wins at Phoenix as Harvick, Truex qualify for Championship 4|
|WATCH: Highlights of thrilling Boca-River Copa Libertadores final|
|PSG coach Tuchel demands more despite Monaco thrashing|
|Boca missed too many chances, rues Schelotto|
|Solari remains tight-lipped on Real Madrid future|
|Hamilton not surprised by Verstappen-Ocon collision|
11. November 2018
|Ronaldo fires Juventus to Serie A record|
|Higuain did nothing serious - Ronaldo hopes Milan striker avoids ban|
|Solari completes perfect Real Madrid audition with fourth straight win|
|Verstappen ordered to do public service after Ocon scuffle|
|Nishikori stuns out-of-sorts Federer|
|Fitzgerald overtakes Owens in career receiving yards|
|Monaco 0 Paris Saint-Germain 4: Cavani hat-trick adds to Henry woes|