The Australian foursome of Gillian Backhouse, Matt Baker, Brittany Dutton and Birtwhistle stuck to their guns to finish second despite dropping to sixth on two occasions during the race.

The result gives Australia a final combined medal tally for elite, age group and paratriathlon categories of nine gold, six silver and nine bronze – second to the US.

The mixed team relay required each of the four team members to cover a 600-metre swim, 6.6km bike ride and 1.6km run.

After losing time trying to get her wetsuit off in transition one, Youth Olympic Games gold medallist Dutton produced a dynamic bike ride and run to put the Australians back in the medal hunt.

She tagged the anchor leg, individual world championship junior silver medallist Birtwhistle, in third place  behind Great Britain and host nation Canada.

Birtwhistle was up against good friend Canadian Tyler Mislawchuk, his training partner and house mate from his Spanish training camp in Vitoria.

After trailing Mislawchuk out of the water, Birtwhistle caught and passed him on the bike.

Both outstanding runners, it was Birtwhistle, one of the fastest under-20 runners over 3000m and 5000m in Australia and this year’s junior Zatopek champion, who held his lead over the 1.6km course to seal second and his second silver medal of the championships.

It also gave Backhouse her second silver of the week after her second-place finish in the under-23 world championship.

For Dutton, it provided a full set of gold, silver and bronze for her championship season, after the 16-year-old’s gold in the Youth Olympic individual race and bronze in the YOG mixed teams relay for Oceania.