Ford’s Mark Winterbottom has defied the pain of a healing broken leg to upstage defending champion Jamie Whincup in practice for the opening race of the V8 Supercar season.

Winterbottom unleashed a late flying lap around the Adelaide street circuit – his 1min 21.8112sec edging out Holden driver Whincup’s 1:21.9315 which stood as the quickest time for most of the session on Friday.

Winterbottom broke his leg eight weeks ago while waterskiing, and admits the injury is still healing.

His Ford Performance Racing teammate Will Davison was third fastest.

Whincup will have several more chances on Friday to reinforce his dominance ahead of the weekend’s two Clipsal 500 races.

There is another practice session scheduled for later on Friday, before qualifying and a top-10 shootout.

Two 250km races will be held on Saturday and Sunday.