Little-known Auckland teenager Michael Poole was the shock winner of the Port of Tauranga Half Ironman in Mt Maunganui yesterday - finishing ahead of the internationally respected Kieran Doe and last year's champion, Duncan Milne, both of whom withdrew during the race.

Poole, who has just left Auckland Grammar, where he was the national secondary schools triathlon champion and a nationally-ranked cyclist, is only 18 but already has his sights set on the Olympics. He clearly has a bright future.

He entered the race with no ambitions of winning the gruelling 2km swim, 90km bike and 21km run, using the day for experience following his win over the standard distance at Whangamata last weekend.

The former Tauranga athlete found himself in contention alongside Glenbrook's James Bowstead after one lap on the run.

Bowstead, in his sixth attempt at the race, was expected to prove too strong on the last tough trek around the Mount base track but Poole broke clear to win in 3h 56m 33s.

Bowstead, who turned 23 yesterday, could not get the perfect birthday gift, settling for second in 3h 58m 12s, following his third place last year.

Australian Tim Berkel, who stood up the leaders seven minutes off the bike, stormed home with the fastest run of to climb through the field to third.

Doe led out of the water and extended to a three-minute lead midway through the bike.

But he faded badly to be caught by Bowstead, who led the chase pack, before the end of the bike and later withdrew on the run.

Bowstead pushed hard on the run to shake everyone but Poole, who took the race to his more experienced opponent.

"I had no expectations here today. I just wanted to get some experience," Poole said.

"I wanted to stay as comfortable as I could on the bike, start the run easy and run the last 5km hard. That's exactly what I did and somehow I won.

"I had dropped him [Bowstead] before the Mount so I knew he was hurting but I also knew he wouldn't give up so I gave it everything.

Poole added: "I'm definitely not interested in racing this distance. My goal is to go on and compete in the Olympics. That's what I want to do. This race was fun but I could never consider Ironman, it was so long out there."

Berkel said he was delighted with his run but would learn about giving up so much time in the swim and bike.

"It was a great race and a really hard day with some winds on the bike and that run around the Mount. But it was a good result and one that I will learn plenty from," Berkel said.

Defending champion Milne (Taupo) withdrew on the bike after suffering from illness on the first lap. World champion rower Storm Uru finished in 18th place in a respectable 4h 24m 37s.

If the men's title was a surprise, the women's winner was demonstrably not so.

Whangarei's Samantha Warriner ran down Swiss leader Caroline Steffen to claim back-to-back honours in the race that doubled as the official Triathlon New Zealand Championships.

The women's race drew the best field in the event's 21-year history, with every winner since 2002 competing. Steffen, the Australia-based Swiss star, showed her class.

The first national squad swimmer and professional cyclist made the most of those skills to lead out of the water and extend away at the front of the field on the bike.

She built a 2m 40s lead on Warriner followed by Joanna Lawn after the bike, but by the midway point the Kiwi Olympian had reduced that margin to 1m 20s.

It took until the final 3km undulating run around the Mount to catch the leader, with Warriner going on to win for the third time, with Steffen second just 18 seconds behind.

Three-time champion Rebekah Keat (Australia), nearly four minutes behind the leader off the bike, had a fast run to move up to third ahead of Lawn.

Warriner, who got married over Christmas and had a disjointed build-up, said she had to work hard for the victory: "I didn't have a good swim at all and went as hard as I could on the bike. I knew if I could keep the gap at around two or two and a half minutes that I was pretty confident I could catch her on the run.".

"I ran really strong to catch Caroline. We know what it is like around the Mount and I used it to my advantage today. It was a hard day out there. I am so pleased to be back and I really enjoyed it. The crowd was amazing - just unbelievable."

Steffen, in just her second year full-time in the sport, was disappointed not to win but said: "I am really happy with second. I had an awesome swim, good bike and I still struggled on the run. I have to work really hard in the next few months on the run. All in all it was a good race for me and I am pretty excited about the future because I am still so young at this sport."