But the series is a long and exhausting one, with 11 more rounds to go before it wraps up in Indiana in October, so it is still early days in the title chase.
Round two started well for Whibley who grabbed the holeshot before the field headed into the woods.
The track was in good shape and things were progressing well until he crossed a little muddy creek filled with ruts where he hit a hidden root and tipped over, dropping back to fourth spot.
Now it was a case of making up lost ground and Whibley pushed hard to regain contact with the leaders, Australian Josh Strang and American Charlie Mullins, but the effort took its toll, the muscles in his arms starting to "pump up" and eventually forcing him to back off and surrender a few positions.
After the first gas stop Whibley began to loosen up but despite riding well he failed to make the expected inroads into the lead and it was clear by the second gas stop that any hopes of making the first three were gone.
Crossing the line in sixth place, Whibley admitted to being "pretty disappointed" with his performance and acknowledged he had some work to do to get back on to the place-getters box by the third round.
The next round of the series is scheduled for Steel Creek, North Carolina, from April 6-7.
