Brown started midway through the list of contenders, a reflection of her standing in the UCI rankings, but she performed well above that positioning.
Brown was fastest at the intermediate time check, with a time of 20 minutes and 35 seconds before finishing the time trial with a time that was 20 seconds faster than the incumbent fastest finisher Emma Norsgaard (Denmark).
The Victorian moved into the hot seat with the hope of holding on as long as possible and had to watch as four riders set faster times through the intermediate time split, before Ellen van Dijk reached the Imola circuit and claimed the fastest time.
Brown eventually finished fifth in her debut in the world championships time trial, with her goal of a strong performance at the Olympics in Tokyo looking a very real possibility.
The 28-year-old posted of her joy at the result on Instagram, saying; "This discipline is so tough in every way, but the reward is truly the best!"
"Lots of hurt out there today on this beautiful course, but I’m super happy with this result. Of course, I’m already thinking about how I can dial things in and step it up another level!"
"I also just want to thank everyone that got behind me for this event and believed in me. All the Australian Cycling Team staff, my coach Felicity Wardlaw and my dear family."
Brown was second to 19-year-old Sarah Gigante at the nationals time trial, the only significant test against the clock for the season to date, but the younger rider wasn't given a position in the world championship squad.
The World Championships continues tonight with the men's time trial from Imola, Italy. Rohan Dennis and Luke Durbridge will fly the flag for Australia, with coverage beginning from 2225 AEST on SBS On Demand and streaming via the Cycling Central website.
