Olympic champion Andy Murray restored some order at the Western & Southern Open by cutting down South African giant Kevin Anderson to reach the quarter-finals on an upset-filled Thursday in Cincinnati.
Rafael Nadal and Stanislas Wawrinka, two of the other headliners at the US Open warm-up event, fell to a pair of young guns on a hot and steamy day on the Ohio hardcourts.
Wimbledon champion Murray, who clutched at his right shoulder after going an early break down to trail 3-2 in the first set, soon snapped into focus to run off four games in a row on his way to a 6-3, 6-2 victory.
Showing off his dazzling variety of shots and remarkable court coverage, Murray extended his winning streak to 20 with his 600th career victory on the ATP Tour.
Third-seeded Nadal, showing fatigue following a busy Olympic schedule that included a gold medal in doubles, was a step off the pace and paid the price against 19-year-old Borna Coric of Croatia, who reached the last eight with a 6-1, 6-3 win.
Elsewhere, Grigor Dimitrov eliminated sluggish second seed Wawrinka, the Bulgarian making the most of a single break of serve in each set to win 6-4, 6-4 and book his berth in the quarters.
Australian Bernard Tomic, 23, notched yet another upset with a 7-6(1) 7-6(5) win over fifth-seeded Kei Nishikori of Japan, who had won the bronze medal match in Rio over Nadal.
Tomic's next assignment will be against Murray, who owns a 4-0 advantage over the Australian in head-to-head encounters.
Kerber's march to the top continues in Cincinnati
Angelique Kerber moved a step closer to turning a dream goal into reality with a hard-fought win over Barbora Strycova to reach the quarter-finals of the Western & Southern Open.
The Australian Open champion's 7-6(5), 6-4 victory over the Czech put the German world number two just three wins away from leapfrogging Serena Williams, absent from this event, at the top of the WTA rankings for a first time.
"It's the goal one day to be number one, but if it happens and when it happens, whatever," the 28-year-old told ESPN, adding that everyone was reminding her how close she was to topping the rankings as she tried to block out the thought.
"I would not be putting this pressure on myself here. I'm just trying to play my best tennis."
Kerber, enjoying her best season, including a Wimbledon final appearance and silver medal in the women's singles at the Rio Olympics, claims here improved serve and on-court attitude have been key to her rise.
Next up for Kerber is Spain's Carla Suárez Navarro, who beat Roberta Vinci of Italy 6-1, 7-5.
Third-seeded Simona Halep notched her 12th win in a row with a 6-1, 6-2 thrashing of Australian qualifier Daria Gavrilova, beating the heat by finishing in 53 minutes.
