Schwartzman the latest seed to fall in Rio
Defending champion Diego Schwartzman became the latest seed to exit the Rio Open, while John Isner had no trouble at Delray Beach on Wednesday.
Schwartzman trailed his first-round clash against 2016 champion Pablo Cuevas 6-1 4-1 when the Argentine fourth seed retired due to a leg injury.
The ATP 500 event saw multiple upsets in the opening round, with Schwartzman becoming just the latest seed to fall.
Of the eight seeds, only one – Joao Sousa – managed to reach the second round, with Dominic Thiem among the casualties.
It has left the draw wide open and Aljaz Bedene, qualifier Hugo Dellien, Jaume Munar and wildcard Felix Auger-Aliassime moved into the quarter-finals.
Bedene beat wildcard Thiago Monteiro 6-3 6-4, qualifier Dellien was too good for Roberto Carballes Baena 7-5 6-4, Munar battled past Cameron Norrie 7-6 (8-6) 5-7 7-6 (7-4) and Auger-Aliassime defeated Christian Garin 7-5 6-4.
Taro Daniel joined Cuevas in the second round after a 3-6 6-3 6-2 win over wildcard Thiago Seyboth Wild.
The Delray Beach Open has seen fewer shocks and that continued as Isner was one of three seeds to move into the last eight.
Isner sent down 18 aces in a 6-4 6-3 victory against Lukas Lacko, who won just one point against the American's first serve.
Adrian Mannarino is next for Isner after the Frenchman overcame Denis Istomin 6-2 7-6 (7-3).
Andreas Seppi and Dan Evans will meet in the quarter-finals after wins over Jordan Thompson and Lloyd Harris respectively.