Stan Wawrinka and Nick Kyrgios were among the players to make a first-round exit at the Shanghai Masters on Monday.
Switzerland’s three-time major winner and former world number three Wawrinka, a wildcard in this tournament, was beaten 4-6 6-4 6-3 by 13th seed Borna Coric in just under two hours.
The Croatian saved two break points at 3-3 in the second set and claimed three of the first four games in the decider.
Coric will now face American qualifier Bradley Klahn, who sprung a surprise as he defeated Australia’s Kyrgios 4-6 6-4 6-3.
Others eliminated on Monday included ninth seed Diego Schwartzman, beaten 6-3 6-4 by Sam Querrey, and 14th seed Milos Raonic, who lost 6-3 5-7 6-3 to qualifier Mackenzie McDonald.
Two more seeds made safe progress as Stefanos Tsitsipas (10th) and Marco Cecchinato (16th) saw off Gael Monfils and Gilles Simon respectively.
2016 finalist Roberto Bautista Agut, Marton Fucsovics, Andreas Seppi, Matthew Ebden, Taylor Fritz and wildcard Yibing Wu also advanced to round two.