It came more than half a century after Australia's recently-deceased triple Formula One world champion Sir Jack Brabham (http://www.motoring.com.au/news/motorsport-sir-jack-brabham-%E2%80%93-a-legendary-life-43541) began the rear-engined revolution in American open-wheeler racing.
Among other Australians, Brabham's eldest son, Geoff, Vern Schuppan, Ryan Briscoe and Power had tried for years to win the title in the series that grew from the Indianapolis 500 until the Queenslander's emotional breakthrough yesterday after missing out on the crown in 2010, '11 and '12.
Power only finished ninth in the final of the 18 rounds this time, but his main rival and teammate Helio Castroneves ended up only 14th and a lap down after a drive-through penalty for a pitlane violation 30 laps from the chequered flag.
Brazilian Castroneves had started from pole position while Power began from second last in the field and had to make up ground with uncharacteristic patience.
Power delivered the 13th North American open-wheeler series title to the Chevrolet-powered team of Roger 'The Captain' Penske – and its first since 2006.
It came two months after Penske was to have decided on whether to enter Australia's V8 Supercar Championship next year or in 2016 – a matter on which there is still no word.
Penske's NASCAR team is in the running for a second Sprint Cup title in three years too – with Ford cars.
But it is his record 15 Indianapolis 500 victories as a team owner – three of them delivered by Castroneves – for which Penske is most famous.
Australia's long-time Formula One driver and nine-time Grand Prix winner Mark Webber, who mentored Power in Europe more than a decade ago, congratulated the Queenslander as a “guy who has worked his ring off for years and never had anything handed to him”.
While Australia's new F1 sensation Daniel Ricciardo had a weekend off after his third victory with Red Bull Racing in the Belgian GP and before next Sunday's Italian GP, the latest Aussie climbing the open-wheeler ladder with distinction, 18-year-old Anton DePasquale, went further ahead in the Formula Renault 1.6 Championship.
More on that below.
It was 2004 IndyCar champion and 2013 Indianapolis 500 winner Kanaan's first year with Chip Ganassi Racing and he took the chequered flag at Fontana 3.67 seconds ahead of New Zealand teammate and last year's champion, Scott Dixon.
Ryan Briscoe was seventh in another Chevrolet-powered Ganassi entry.
Power struggled with his car's handling late in the race and realised he wouldn't win it, but Castroneves' error – which the Brazilian called “my bad” – made his job easier.
Had Castroneves won Power would have needed to have finished at least sixth.
“That was one of the hardest races ever,” Power said.
“It went on and on (250 laps of the 2-mile, or 3.2km, super-speedway built by Penske 17 years ago), and I slowly made up positions.
“This is surreal, man. Just a fantastic way to finish the season. I can't believe I'm the champion.
“It's [the culmination] of 15 years of hard work. I was crying over the [finish] line.
“I am so mentally exhausted now. That was mega.”
Power had gone into the double-points finale 51 points ahead of Castroneves and wound up 62 in front.
Penske's third driver, Colombian Juan Pablo Montoya, who started alongside Castroneves on the front row, led the most laps (85), with Kanaan next (64) and then Castroneves (41).
Castroneves admitted that missing out on the title for the fourth time “stings a little bit” and his bonus for finishing runner-up was “only” US$250,000 – a quarter of Power's – but was pleased at the success of Team Penske, which he called “an amazing organisation”.
Power was one of nine drivers to lead at Fontana, but only for eight laps after the only caution period of the race.
American Ed Carpenter, who only contests oval rounds in the series, finished third, ahead of Montoya in his first season back in IndyCar after his stints in F1 and NASCAR.
Frenchman Simon Pagenaud, the third genuine contender for the title, had a horror race – he was the last finisher, seven laps down – and wound up fifth in the championship but the highest of the Honda-powered drivers.
Pagenaud's Schmidt Peterson Hamilton Motorsport teammate, Russian IndyCar rookie Mikhail Aleshin, missed the race after a terrible crash in the lead-up.
Aleshin, who beat Daniel Ricciardo to the 2010 World Series by Renault (also called Formula Renault 3.5 Championship) in Europe, suffered chest injuries, fractured ribs, a broken collarbone and concussion as the fourth Ganassi driver, American Charlie Kimball, miraculously avoided injury when he could not avoid Aleshin's out-of-control car.
DePasquale, from Werribee near Melbourne, was baulked at a restart in the ninth race of the Renault 1.6 series at Belgian's Zolder circuit and finished fourth as his Austrian teammate in the Lechner Racing Team, Florian Janits, notched his maiden win.
However, the Australian rebounded in race 10 with what was described as “a flawless and dominant performance” to take the chequered flag 3.5 seconds clear for his sixth win of the season.
He's also had three second places and leads the series by 53 points, with two rounds remaining – at Spa-Francorchamps in Belgium and Zandvoort in Holland.