Australia’s last remaining hope in the Delray Beach Open has been beaten, with John-Patrick Smith going down in straight sets to veteran Juan Martin del Potro.

Qualifier Smith was beaten 6-4 6-4 by the experienced Brazilian, who is playing his first ATP tournament in 11 months due to wrist surgery.

Smith’s defeat completed a horror week for the Australian contingent with Bernard Tomic (tournament No.2 seed), Sam Groth, Matthew Ebden and John Millman all crashing out in the first round.

Earlier Tim Smyczek made good use of his wildcard by beating tournament No.7 seed Donald Young, last year’s runners-up, 1-6 7-6 (7-2) 6-2.

The 28-year-old Tampa resident followed that up with a win over seventh-seeded Donald Young, last year’s runner-up, 1-6 7-6 (7-2) 6-2 to reach only the second tour-level quarter-final of his career.

“I was feeling good mentally even though I was getting my butt kicked,” said Smyczek, who had played Young 11 previous times in futures and challenger events but only once before at the tour level.

“I was just trying to figure out a way to disrupt his rhythm. I knew I needed to change my game plan and stop being so offensive.”

Fifth-seeded Frenchman Jeremy Chardy fought through swirling wind to beat 19-year-old American wild-card Noah Rubin 6-4 6-2 to reach the quarter-finals.

Chardy joined fourth-seeded Bulgarian Grigor Dimitrov of Bulgaria as one of only two seeded players left in the draw.

Chardy was down 2-0 to Rubin before winning 12 of the next 16 games. He will play del Potro while Smyczek will face American Sam Querrey.

“I think it was really difficult to play today because of the wind,” said the 29-year-old Chardy, currently ranked No. 30. “It was turning and changing so much. Today, the level was not important. I just wanted to get the win.”