Supercars star Jamie Whincup believes the defection of a Triple Eight stalwart is behind the 2017 rise of rivals DJR Team Penske.
French engineer Ludo Lacroix controversially switched teams after last year's championship, a move Triple Eight Race Engineering boss Roland Dane labelled duplicitous at the time.
Since his switch, DJR Team Penske have gone from also-rans to title challengers, with New Zealand pair Scott McLaughlin and Fabian Coulthard hot on the heels of Whincup in this year's championship race.
Whincup holds a slender 17-point lead heading into this weekend's Auckland SuperSprint event in New Zealand.