In one of the most absorbing contests of the Rio Olympics, Brown taunted the centre court crowd, who were quite animated in their support for local boy Thomaz Bellucci.

The crowd repeatedly booed his winners and cheered his faults, with a large portion of the crowd cheering when he hit the deck in agony after rolling his ankle in the second set that forced him to retire from the match.

But when he eventually returned to his feet he was given a standing ovation by the one-sided crowd, showing their respect for the German entertainer as he trudged off centre court with his Olympic aspirations down the gurgler.

The 28-year-old Brazilian booked his ticket into the second round after Brown was forced to retire following an ankle sprain that left the world No.86 in agony rolling on the deck unattended by medical staff for over a minute.

Brown had won the first set 6-4 and was attempting to hold serve at 4-4 in the second when he rolled his ankle, eventually returning to surrender the break and throw in the towel.

"I'm happy to be in the second round but I'm very sad to see a friend with a serious injury," Bellucci said.

"I hope it's not too serious and see Dustin soon in the tour. It was a lot of fun. I think Dustin was enjoying a lot the atmosphere. For me it was amazing to play in the Olympic games in my country was amazing. The experience was unbelievable. For me it's a very special tournament."

Brown was taken straight to hospital for scans on the injured ankle and it's unclear whether he will be fit in time for the US Open.