Rafael Nadal, the world number one, has dropped the strongest hint yet that he could pull out of the ATP World Tour Finals after admitting he is not yet certain of participating in the season-ending tournament in London. Federer got to it and hit a backhand victor.
'We all needed to be ready to take that advantage and I would say that Roger came out of the blocks a little bit better than Rafa.
Cilic, meanwhile, must put thoughts of this agonising loss behind him as he prepares for a must-win match with Jack Sock. Former Wimbledon semi-finallist Tim Henman said on BBC commentary: "It's slightly weird because you see him walking around in between points or away from the court, the limp is quite pronounced".
The Spaniard who is already assured to finish as world number one will be hoping he can overcome a knee injury picked up whilst playing at the Paris Masters.
'They played the best season on the tour and they deservedly are at the top.
"Then when you see him moving on the court, his movement is improving".
On the rest of the tournament: "I'm going to play Jack (Sock) next match".
Both players saw humour in the incident, but it was Federer smiling when he wrapped up the set a matter of minutes later.
Zverev will move on to a meeting with Roger Federer on Tuesday, a player he beat to win the Montreal Masters earlier in the year.
More errors had crept into the Zverev game and although the youngster got the help of Hawk-eye to deny Cilic a set point, the Croat soon served out to square the contest.
"It was a big distraction", said Federer. That's what I should have aimed for. "It has happened sometimes in the past but not on a big stage like this".
Chung, 21, was outplayed in the first set and was 3-1 behind in the second set before taking over to win 3-4 (5-7), 4-3 (7-2), 4-2, 4-2 to complete the five-day tournament unbeaten. It was all much more emphatic than 6-4, 7-6 suggested.
"But then turning it up the last few days got me in shape for today". "There's no more turning back, just full steam ahead every match that comes".
- Trump offers to 'mediate' on South China Sea disputes
- Poles march alongside other European nationalists in Warsaw
- Gossip columnist Liz Smith dies at 94
- Lions activate Taylor Decker from PUP list ahead of Browns game
- San Diego Stairwell Collapse Injures 21 Children In Barrio Logan Gym
- Redskins' Maurice Harris Makes One-Handed Touchdown Catch
- NASCAR at Phoenix 2017 Results: Matt Kenseth Wins, Brad Keselowski Advances
- Carrie Underwood injured in fall at home
- North Korea says Trump 'begged for a war' during his Asia trip
- Liam Payne Takes the Stage at MTV EMAs 2017