As it happened, Gao turned 16 before the start of the 2020-21 season, which was delayed due to COVID-19. His first tournament was the Championship League. Gao made 2-2 draws against Ben Woollaston and Si Jiahui, but lost 3-1 to Matt Selt. He finished his first day as a professional 3rd in the 4-player group but had made two century breaks.