Whibley said he was looking forward to further embellishing his career credentials with more US glory in 2013.
"There were many fun OMA races in 2012, with some awesome competitors, riders such as Nick Fahringer and Russell Bobbitt. To say these guys were hungry for a win is an understatement - they were starving.
"They both pushed hard and I had some of the closest and most fun battles of the year with these two top dudes," said Whibley.
"In the GNCCs, it all kicked off in Florida with an intense battle with Charlie Mullins right to the line, where we both basically collapsed in a heap.
"Kailub Russell proved to be the biggest challenge of the season.
"We were separated by just one point going into the last round after 36 hours of racing."
Whibley accepts it will be hard to repeat his double title-winning exploits of 2012 but remains a favourite to win in 2013, regardless of which international stars line up alongside him.
The season is long and gruelling with the 13-round 2013 GNCC series kicking off in Florida in March and wrapping up in Indiana in October.
Whibley is supported by Monster Energy, Sargent Yamaha in Masterton, MotoSR suspension, BikesportNZ.com, Graphic MX Creation and Yamaha New Zealand.