“I think everybody knows Tomas is a very good fighter, so I need to fight on every point,” Muller commented. “It was a great match; great match. The match point is a little bit the image of the match. I’m exhausted right now but happy to get the win.

“Tomas is like all the Argentinian and Spanish players who want to take the game with the forehand. I was trying to play a little bit down the line with my backhand to make him run. So that was the tactic today, (plus) some drop-shots.”

It has already been an impressive week for the Frenchman, who opened with a defeat of Buenos Aires champion Joao Fonseca (6-1, 7-6 (4)) that crushed the hopes and dreams of the Brazilian fans.

Muller will face Argentina’s Francisco Cerundolo in the quarters. Cerundolo was the Buenos Aires runner-up to Fonesca.

Etcheverry, ranked No 43 and seeded No 8, beat Frenchman Corentin Moutet(6-3, 7-6 (1) in the Rio de Janeiro first round.

Rio de Janeiro ATP 500, other second-round results:

• Francisco Cerundolo beat Luciano Darderi: 6-7 (1), 6-3, 6-2
• Camilo Ugo Carabelli (LL) beat Damir Dzumhur: 6-4, 6-4
• Jaime Faria (LL) beat Jaume Munar: 6-4, 2-6, 6-3
• Chun-Hsin Tseng (Q) beat Thiago Monteiro (WC): 6-7 (4), 6-3, 7-6 (4)
• Alexander Zverev (1) beat Alexander Shevchenko: 7-6 (1), 7-6 (6)
• Sebastian Baez (5) beat Mariano Navone: 6-4, 1-6, 6-3
• Francisco Comesana beat Nicolas Jarry (6): 7-6 (4), 6-7 (1), 7-6 (6)