Roger Federer set up an intriguing all-Swiss quarter-final encounter against Stan Wawrinka with a dominant victory over Leonardo Mayer at the Cincinnati Masters.
The world No 2 was the headline act of a busy schedule as the rain-hit Masters 1000 tournament was left with a backlog of last-16 matches to complete due to Thursday's early suspension to play.
Federer, a seven-time Cincinnati champion, defeated Mayer 6-1 7-6 (8-6) in 72 minutes to complete the first part of a likely double-header.
The 37-year-old breezed through a one-sided first set in 23 minutes, winning five games on the bounce against the world No 50.
Mayer offered greater resistance in the second set forcing Federer into a tie-break and, despite surrendering a 5-1 advantage, the Swiss player avoided a deciding set by closing out the match with his 10th ace.
Federer needed only 72 minutes to defeat Leonardo Mayer in their third meeting
The 20-time Grand Slam champion, preparing to bid for a sixth US Open title and first at Flushing Meadows in a decade, will next meet Wawrinka after his compatriot completed his held-over encounter against Marton Fucsovics in straight-sets.
Roger Federer has won 20 of his 23 matches against Stan Wawrinka, last losing to his compatriot at the French Open in 2015.
Wawrinka, returning to form and confidence, was involved in a three-set thriller with his Hungarian opponent in Toronto last week but this time enjoyed a rather more routine 6-4 6-3 victory.
Novak Djokovic, chasing the Cincinnati title to complete the Masters 1000 collection, concluded his weather-affected encounter with defending champion Grigor Dimitrov, winning 2-6 6-3 6-4 to book a meeting with Milos Raonic.
Novak Djokovic completed a three-set win over defending champion Grigor Dimitrov
The opening match of the day saw Juan Martin del Potro defeat Nick Kyrgios 7-6 (7-4) 6-7 (6-8) 6-2.
After the first two sets were decided in tight fashion, with neither player being broken, Kyrgios appeared to lose focus after Del Potro took a nine-minute bathroom break prior to the deciding set.
Del Potro will next meet Belgium's David Goffin in the last-eight after he secured an impressive 6-2 6-4 victory over Wimbledon finalist Kevin Anderson.
Marin Cilic also returned to book safe passage to the quarter-finals, where he will meet Pablo Carreno Busta, as he defeated Karen Khachanov 7-6 (7-5) 3-6 6-4.
Juan Martin del Potro proved too strong for Nick Kyrgios