New Zealand's top mountainbikers are celebrating their most successful UCI World Cup showing, at Mont Sainte Anne in Canada.

Christchurch teenager Anton Cooper scored a runaway victory in the junior men's cross country in a dominant performance today, adding to the two medals earned by Samara Sheppard and Amber Johnston in the under-23 and junior women, respectively, yesterday.

The 2009 junior world champion, Brook Macdonald of Napier, roared down the rocky course to finish sixth in the elite men's downhill where four Kiwi riders finished in the top 11.

It is the first time New Zealanders have earned three medals in cross-country in the same World Cup competition while New Zealand now has five riders in the top 15 on the standings in downhill, the most of any nation.

Cooper, 17, who rides for Trek World Racing, was in a class of his own in the junior men's competition. He was a minute ahead after the start loop, three minutes clear after lap one and he eventually won the 20.57km race by more than six minutes from second-placed Marc-Antoine Nadon of Canada.

On lap times, Cooper compared with those inside the top 15 times in the elite race, and he remains unbeaten after two rounds this year.

"The thing was not knowing what to expect in comparison with the other riders, so it is good to turn up here and do this one and get a good judgement of where I am at before turning up for worlds. I was feeling confident because I had lab testing and the results indicated I was in pretty good form. I knew I had the strength so it was a matter of going out there and doing it."

He was pleased with the performance given he had come out of winter conditions in Christchurch.

"It's been so cold with snow and ice at home. It's been tricky in the last two weeks so to get over here where it is so hot was good. The first couple of days were a bit of a shock, but I am getting in to it now and pretty happy with my form."

New Zealand's burgeoning group of downhill racers were all in top form on the brutal and rocky course at Mont Sainte Anne.

Macdonald (MS Mondraker) led the way in sixth place, his best of the season. The Napier rider was very fast over the opening section although he made two small errors through the rocky mid-section before powering home in four minutes 17.907 seconds, less than 4s behind the winner, American Aaron Gwin.

Wanganui's Sam Blenkinsop (Lapierre International) sat in the hot seat as the fastest rider for some time after his slick 4:19.161 before the latter riders including Macdonald went faster, finally settling for a season-best ninth place.

Dunedin's Justin Leov (Trek World Racing) also pushed into the top-10 for the first time this year with a 4:19.655, just ahead of Christchurch's Cameron Cole (Lapierre International) who was 11th in 4:20.037.

The World Cup moves across the border to Windham in upstate New York for both cross-country and downhill next weekend.

- © Fairfax NZ News