They didn't need to worry: The pride of Toowoomba, Australia, finally is a champion.
Roger Penske's team completed a dynamic season by claiming three of the top four spots in the overall standings, with fourth place wrapped up by Juan Pablo Montoya, who led the most laps at Fontana.
Power and Penske jointly held up an Australian flag on the victory podium before Power raised the Astor Cup.
"There's no question that Will deserves this championship," Penske said. "He won a number of races, a lot of poles, and really brought some momentum to this team. He deserved it. He was the best road racer, and to see him operate on the oval this year showed me he's got it."
Castroneves was essentially finished after a drive-through penalty for a pit entry violation with 31 laps to go, sliding out of the groove onto the track on his way into the pits. The penalty paved a championship finish for Power, who has been dinged numerous times this season by pit road penalties.
For the sixth time in his career, Castroneves missed the title despite entering the final two IndyCar races in the top two in the points standings.
"It stings a little bit, but that's what motivates me," Castroneves said. "It's good to be upset when you finish second in a championship. It gives me another reason to come back stronger next year and fix what we can fix to win a championship."
Power beat Castroneves by 62 points for the title. Scott Dixon, the 2013 series champion, ended up third in the standings after a strong finish to the season.
Rookie Mikhail Aleshin's frightening crash late in a practice session reduced the field, but it didn't change Power's strategy. He was concerned by multiple crashes in the Fontana race in previous seasons, including his own spectacular flop in 2012.
Instead, the race was nearly uninterrupted — and Power did everything correctly.
"That's 15 years of hard work," Power said. "It's just surreal, man. I can't believe it."