Former world No. 1 Serena Williams looked sharp in her return to the hardcourts after a week-long break, soundly defeating Daria Gavrilova 6-1, 6-2 on Monday to advance to the second round of the Cincinnati Masters.
Federer and Williams were making their first appearance at the tournament since they each won the title in 2015.
After suffering the worst defeat of her career to Johanna Konta in San Jose, Williams withdrew from the Rogers Cup for personal reasons, and later revealed she had been struggling with the emotional challenges of balancing motherhood with her career.
Playing his fourth tournament after missing nearly a year due to an ongoing hip problem, Murray tallied eight double faults and was broken four times in a rusty display.
"I know it's also for player protection and injuries", he said. And people were asking him 'What, you're not going to play the grass?' And then he should have won Queens and goes on to win Wimbledon, so things can turn very quickly, regardless if you're positive or not, sometimes when you just put yourself out there and then you get excited in a quarters of semis of a Slam you can start playing your best tennis.
"I would probably add more best-of-five-set matches in finals", said the world No.2 after his Cincinnati Masters second-round win over Peter Gojowczyk. "I have more time for the family, which is important for me", the father of two sets of twins said.
"This year has been tough, " Kyrgios said.
Djokovic is at the other end of the spectrum and believes that even Grand Slams should do away with the best-of-five format. I think that's the seventh match I've played.
Kyle Edmund also went out in the second round, losing in straight sets to the 19-year-old Canadian Denis Shapovalov.
"We have been definitely thinking about the options with my hip". You know, there is only so much you can do before you have to get surgery or something like that.
"Right now I'm just managing it".
But 10th seed Djokovic got his bid off to a winning start in a hard-fought 6-4 7-6 (7-4) victory over American opponent Johnson. Ashleigh Barty stopped wild card Marketa Vondrousova 6-3 7-5.
The victor of that match will play Lesia Tsurenko, who defeated Ekaterina Makarova 7-6 (7/5) 6-2.