World No. 1 Novak Djokovic became the only Top 8 seed to reach the quarterfinal stage at the 2019 Western & Southern Open, advancing past qualifier Pablo Carreno Busta, 6-3, 6-4, in Cincinnati Thursday.
The ATP Masters 1000 event began with second seed Rafael Nadal, fourth seed Dominic Thiem and 10th seed Fabio Fognini all withdrawing, but soon saw numerous seeded contenders fall by the wayside in a string of upsets. Fifth seed Stefanos Tsitsipas, sixth seed Kei Nishikori and seventh seed Alexander Zverev all crashed out in their openers. Third seed Roger Federer and eighth seed Karen Khachanov added to the seeded exodus Thursday, leaving No. 9 seed Daniil Medvedev as the only Top 10 seed in the last eight until Djokovic joined the Russian.
Djokovic, who completed a Career Golden Masters last year by winning his first Cincinnati crown, needed just one break of serve in each set to defeat Carreno Busta.
"A very good performance from my side. At least two levels better than against Querrey in the first match," Djokovic assessed. "I'm pleased I'm going in the right direction and looking forward to the next one."
The Serbian will continue his title defense against Lucas Pouille on Friday after the Frenchman topped Khachanov, 6-7 (3), 6-4, 6-2, in just under two hours. Djokovic has won nine consecutive matches, dating back to lifting his 16th major trophy at Wimbledon.
The 23-year-old Medvedev breezed past Jan-Lennard Struff, 6-2, 6-1, and will battle Federer's conqueror, Andrey Rublev, for a place in the semifinals. Medvedev, a winner of 40 matches this season, is coming off back-to-back final showings in Washington D.C. and Montreal, his first ATP Masters 1000 title match appearance.