Novak Djokovic booked his spot in the quarter-finals of the Western & Southern Open, but Andy Murray's campaign came to an end.
Djokovic – the top seed – eased past Tennys Sandgren at the 1000 tournament in New York, where the event is being held instead of Cincinnati due to the coronavirus pandemic.
Former world number one Murray, meanwhile, fell to Milos Raonic in straight sets.
Daniil Medvedev and Stefanos Tsitsipas all advanced as last year's runner-up David Goffin was sent packing.
DJOKOVIC FINDS FORM
Hampered by a neck problem in his opening-round match, world number one Djokovic showed no physical issues as he accounted for Sandgren 6-2 6-4.
The 17-time grand slam champion improved to 20-0 in 2020 and will face Jan-Lennard Struff in the quarter-finals. It is his 84th ATP Masters 1000 quarter-final, only trailing Rafael Nadal (92) and Roger Federer (87).
"I'm as close to [being] painless [in my] neck as I can be," Djokovic said. "I'm feeling very good and that has obviously positively reflected on my game today."
Struff upstaged seventh seed Goffin 6-4 3-6 6-4.
RAONIC ENDS MURRAY DROUGHT
For the first time in more than six years, former world number three Raonic defeated Murray thanks to a comprehensive 6-2 6-2 victory.
Three-time grand slam winner Murray had stunned Alexander Zverev en route to the last 16, but his run was ended by Canadian Raonic.
After torrential rain suspended play, Raonic snapped an eight-match losing streak against Murray, who is on the comeback trail ahead of the US Open.
Through to his fifth Western & Southern Open quarter-final, Raonic will play Filip Krajinovic after the Serb eliminated qualifier Marton Fucsovics 6-2 6-1.
TSITSIPAS, MEDVEDEV PROGRESS
Russian third seed and 2019 US Open finalist Medvedev eased past qualifier Aljaz Bedene 6-3 6-3 in less than 70 minutes to set up a quarter-final against eighth seed Roberto Bautista Agut.
Bautista Agut rallied to beat 11th seed Karen Khachanov 4-6 6-3 6-2.
Tsitsipas – the fourth seed – outlasted big-serving American and 2013 runner-up John Isner 7-6 (7-2) 7-6 (7-4).
Bidding to reach his third consecutive final on the ATP Tour, Tsitsipas will face another big-serving American – Reilly Opelka, who trumped sixth seed Matteo Berrettini 6-3 7-6 (7-4).