Mike Dawson's Olympic dreams came to a shuddering halt in "around 13 tonnes of fierce whitewater" but his canoe slalom debut in London had a definite silver lining in London overnight.

The 25-year-old missed gates 19 and 20 in his K1 semi-final run at the Lee Valley course, picking up 100secs' worth of time penalties and pushing him out of final contention, eventually finishing a creditable 15th.

Kiwi kayaker Mike Dawson missed out on a K1 finals spot at the Olympics.

However, it meant he could relax for the final and see his training mate, Czech Vávra Hradilek, pick up silver behind Italian champion Daniele Molmenti.

The pair trained together in Rotorua during New Zealand's summer, including running an extreme slalom course on the Kaituna River with the express purpose of preparing for the Olympic final. The pair set up the course on a rain-swollen series of waterfalls, knowing how heavy Lee Valley would be, and for Hradilek at least, it paid off in style.

"I'm so stoked for my bro Vavra - he's worked so hard for this and to see him pick up a medal capped an amazing day," Dawson said. "It was a wicked experience to line up in an Olympic semi-final and I'm gutted I couldn't deliver today but Gate 18 was definitely a lot harder than I thought!

The cool thing for me is I had a pretty good run until gate 18 and I was up there until then, which is something I can take away and use in preparation for Rio in four years' time."

Dawson's immediate plans revolve around supporting fellow Waiariki Academy of Sport paddler Luuka Jones, who has qualified for the women's K1 semi-finals tonight, enjoying the London party, then getting back into his plastic creek boat and running some big water on the American extreme race circuit.

He's been blown away by the support he's received from all over the globe but especially back home in Tauranga and Rotorua, and leaves his first Olympic campaign confident he gave it everything.

Molmenti, meanwhile, let out a loud scream as he crossed the line, flexing his biceps for the cameras as he looked up and saw his winning time.

The current European champion, who could only manage 10th in Beijing, won in a time of 93.43, 1.35secs ahead of Hradilek, with Germany's Hannes Aigner claiming bronze.

Jones was a fascinated, although slightly nervous, spectator at the men's final as she prepares for the finale of the women's K1 tonight.

"It definitely won't be easy out there but I'm fired up and want to leave London proud of my paddling and performance," the 23-year-old said. "We've been getting fantastic support and messages from home and that's a cool thing to take onto the course with me."

See Dawson and Hradilek's incredible Kaituna session here: