Dideriksen fought off the challenges of Italy's Sofia Bertizzolo and Poland's Agnieszka Skalniak, who claimed the silver and bronze medals respectively, to join Great Britain's Nicole Cooke and Lucy Garner on an exclusive list of back-to-back champions.

The peloton largely remained together for the first three laps of the 18.2 kilometre circuit and the key moment came after Italy upped the pace at the front in the last of four laps, firing two riders, Bertizzolo and Sofia Beggin, up the road on the final ascent of the Mirador climb.

Dideriksen bridged across as the two Italians hesitated and the front peloton of around 20 riders reformed shortly before the final dash for the line.

Bertizzolo made a brave bid to take the gold, surging fast on Dideriksen's left, but the Dane had no problem upping her pace slightly to take her country's first gold of the Championships.

Kurt-Asle Arvesen (centre) was the last Norweigan to win the under-23 men's road race in 1997 ©Getty Images



"I'm very happy, I was not expecting this," said Dideriksen.

"I thought a lot of my rivals would keep an eye on me because of last year and it was a very different race to last year too."

"This time round everybody knew me.

"So it's amazing to get another gold."

Meanwhile in the under-23 men's road race, Norway's Sven Erik Bystrom secured his country's first gold medal in the event since Kurt-Asle Arvesen in 1997.

Australia's Caleb Ewan secured silver with Kristoffer Skjerping capping an excellent team performance for Norway with the bronze medal.

Bystrom, who will join Team Katusha next year, attacked from the main bunch on the summit of the final climb and managed to hold off counter attacks until the finish.

"It was unbelievable," said Bystrom.

"I felt really good the whole time.

"I took it easy in the beginning to save my legs for the final and I put in the right move at the right time."