Realising undercover police officers were waiting off court was the moment Oliver Anderson knew he had been rumbled.
Anderson had just lost in the second round of an ATP Challenger tournament, but it was his previous match - a three-set comeback win - that sparked the attention of the authorities.
"Anyone who was watching that match would have instantly thought something was up," the Australian recalls.
In January 2016, Anderson won the Australian Open boys' singles title in front of a home crowd, demonstrating his potential in a field featuring future top-10 stars Stefanos Tsitsipas, Felix Auger-Aliassime and Alex de Minaur.