Ymer lost the first set in a tie-break but put himself in a strong position in the second set against Taiwan's Hsu Yu-hsiou and was serving for the set at 5-3 when the physical problems set in.
The Swedish tennis player suddenly collapsed on the court, and the umpire rushed over while world No. 268 Hsu brought over an ice towel. Ymer then got back up but collapsed again moments later. Officials and medical staff then rushed to the scene, while ball kids stood over him, holding towels to provide him privacy.
After a medical time-out, Ymer tried to play on, but at 5–5 he chose to retire from the match. As he walked to the net to shake hands, the Swede was limping heavily.
According to the ATP, nausea was the cause of the collapse, while extreme weather conditions and high humidity were also believed to have contributed to Ymer's physical exhaustion and sudden collapse during the intense rally.
Ymer is currently ranked 212 in the official ATP singles world rankings.