Iden stopped the clock at 3:52:35 with Brownlee 2:43 behind in second, a further 86sec clear of local favourite Rudy von Berg, who grew up in the region but represents USA. 

Last weekend’s World Triathlon Series Grand Final winner Kristian Blummenfelt was fourth, ahead of two-time 70.3 champion, Sebastian Kienle, Bart Aernouts and Spain’s multiple world champion Javier Gomez. 

Britain’s George Goodwin, the Ironman Staffordshire 70.3 winner, also produced a noteworthy performance in only his second season as a professional, as he moved through the field on the bike to eventually finish 12th.

“The swim was good and out on the bike I was on my own early doors giving it everything,” Brownlee said. “I got caught by Rudy and Gustav a couple of Ks down the descent [on the bike] and I felt good [on the run] for three or four Ks, but by 5km that was it, I was ready to finish. I don’t know what happened, maybe I pushed it too hard on the bike, or the heat, or whatever. I’m a bit disappointed but held on for dear life.

“I knew Gustav would run well. I’d been running well in training and was in shape to run a really quick half-marathon, but didn’t have the legs. I’ve trained hard for this and will try and put it all into Kona now and see how it goes.”

Iden’s race-best 1:08:10 half-marathon against Brownlee’s 1:10:43 proved the difference, but while the Norwegian may not have enjoyed the highest profile in the lead-up to the event, his performance should raise few eyebrows.

He already holds the second fastest time ever over the distance (3:29:25), which he set in Bahrain in December in finishing runner-up to Blummenfelt in an all-Norwegian podium, and had already won a 70.3 title in Norway as a 20-year-old in 2016.

He has also enjoyed his best year summer of short course racing in 2019, coming fresh from a fourth place finish in Lausanne in the World Triathlon Series Grand Final that backed up the same result in the Tokyo Olympic test event a fortnight earlier.  Iden also made the podium in the WTS Bermuda for a second consecutive year in April.

Despite the victory, which also stood out for Iden riding a road bike as opposed to the more popular time-trial alternative, the Norwegian stressed his immediate future lies very much over the shorter distance, 

“It’s still the Olympics I’m going for,” he said. “It’s the ultimate thing you can do in sports. I’d love to do more long distance and a full Ironman, but now I have to go for what matters the most and that’s the Olympics. I would love to do Kona one day, though.”

Asked about his choice of bike which, despite the hilly course that wended into the Maritime Alps, bucked the trend of the rest of the field, he said: “I think a TT bike would be faster, but I don’t really have any sponsors for a suitable TT bike. Well, I have a TT bike, but it’s without brakes, so probably a good job I used a road bike.”

Australian Josh Amberger led out the 50-strong starting field in the 25.6 degree waters off the Cote d’Azur with Brownlee tucking into his slipstream and Blummenfelt, Gomez, Von Berg and Britain’s Adam Bowden all in close contention.

Amberger was back on the beach just 23:15 later, with the pace proving too hot for Ironman world champion Patrick Lange, who was 76sec adrift, and Kienle, at almost 4mins back.

From there Brownlee took control and burst quickly to the front of the 90km ride with American Ben Kanute for company as the duo whipped through the streets of Nice before commencing the assault on the Col de Vence.

Australian Sam Appleton, a 13-time 70.3 winner, pushed himself into the mix, but last year’s third-placed finisher and one of the pre-race favourites Gomez was among those struggling to live with Brownlee’s climbing prowess.

With a total vertical ascent of 1,367m the field was being splintered, but it was Iden, who looked to be showing no ill-effects from his previous weekend’s endeavours, who came past Kanute into second.

Brownlee passed the halfway mark and led over the top of the climb, but Von Berg swept past the two-time Olympic champion on the descent. As they headed back into Nice for the final 10km of the bike, Von Berg, Brownlee and Iden had opened a 3min gap on Kanute, with Blummefelt 4.22 behind and the big biking American Andrew Starykowicz muscling himself into sixth.