Drizners staged a stunning late fightback to claim Saturday's road race at Buninyong at the Australian road cycling championships.
Queensland's Elliot Schultz made the bold decision to break out with four laps to go on the tough 139.2km circuit, and the move almost paid off.
But he was caught on the final lap and Drizners went into a tense sprint battle with Sebastian Berwick over the final few hundred metres.
"I felt this fire in my belly and I was just so focused and drilled to get the win. It was just a matter of being patient," Drizners said.
"But obviously there was excitement as well. I knew I had a better sprint than him (Berwick) and I went quite early with 300m to go. It ended up paying off and I won by a decent margin."
Berwick finished second, with BridgeLane's Alastair Christie-Johnston third.
Drizners relinquished last year's Under 23 criterium title on Friday, but the 20-year-old only spent 24 hours without a green and gold jersey. To take up his pro contract, Drizners had to withdraw from the national track academy, which could have led to an Olympics appearance in Tokyo.
He will head overseas to link up with Hagens Berman Axeon next month and felt his current form had justified the biggest decision of his career to date.
"This win is a good confidence boost going into the 2020 season. I worked really hard for this race, so it feels special to come away with the win," Drizners said.
"I'm looking forward to getting over with the team and having a great season with them. It's going to be nice having (the jersey) over in Europe in a few races."
Earlier on Saturday, Haylee Fuller completed a big few weeks for her Dubbo club by adding the junior women's road race to the criterium title she won on Friday.
Fuller, competing in the under-19 category for the first time, finished ahead of Alyssa Polites, Catelyn Turner and reigning junior champion Francesca Sewell.
Victoria's Declan Trezise (Darling Downs) won the junior men's road race ahead of defending champion Patrick Eddy (Bendigo & District).
Trezise won the criterium, while Eddy won the time trial.
