Fasnacht was in medal contention in the junior women's road race but was cruelly felled in the final kilometre. In the men's U23 road race, Hindley animated the race in two breakaways, but it was ultimately Callum Scotson who finished highest of the Aussies in 22nd.
Women's Junior Road Race
Fasnacht was sprinting for at least silver before a touch of wheels with Ukrainian Olha Kulynych brought the lone Aussie down. But the junior women's time trial bronze medallist quickly resaddled to claim 14th on the 76 kilometre route in Bergen, Norway.
Pirrone claimed the rainbows after working hard to hold off the bunch the entire final lap.
Earlier, Fasnacht countered a move by Sophie Wright (Great Britain) and Letizia Paternoster (Italy) the third time up Salmon Hill, the Aussie's acceleration forcing a selection of around 15 riders.
But Pirrone fired up the afterburners on the descent to the start/finish line, quickly gaining a 14 second advantage on the start of the final lap.
On the final ascent of Salmon Hill, Wright, Paternoster and Fasnacht were active again, the Tasmanian's acceleration this time reducing the main bunch to seven riders. But the run-in to the finish saw the bunch re-form to around 13 riders with Emma Jorgensen (Denmark) outsprinting Paternoster for silver.
Fasnacht was able to joke despite her disappointment.
"I wish there was more climbing and less descending," she said in a post-race interview with Cycling Australia.
"I didn’t want it to come down to a sprint so with two laps to go, some girls attacked and I went with them, but then they were just sitting up so I kept going. I reached them, and then went again."
"I was hoping some girls would come with me but they didn’t, and then it just split up the field heaps and we dropped the non climbers."
Men's U23 Road Race
Australia's Jai Hindley briefly joined an initial move of 11 riders who were away until halfway through the 191- kilometre course. But a charging peloton led by the home Norwegian team caught the breakaway with four laps to go.
Hindley then went with a new move of Rasmus Tiller (Norway), Scott Davies (Great Britian), Pavel Sivakov (Russia), Brandon McNulty (United States) and Yevgenly Gidich (Kazakhstan) that quickly built a minute's advantage. Back in the pack, Aussie Robert Stannard marked each attempt to try and bridge to the leaders.
But the race came back together the second last time up Salmon Hill, Australia's Stannard, Scotson and Michael Storer all present in the reduced peloton.
France's Benjamin Thomas pulled away before the final ascent of Salmon Hill and was joined by teammate Valentin Madouas, Storer, Wilmar Paredes (Colombia), and Mauricio Moreira (Uruguay).
But a fast moving peloton caught the leaders, Lennard Kamna (Germany) and Cosnefroy edging away from the bunch in the final three kilometres.