1986 was an eventful year for Lamb. He played much of the opening rounds at halfback with captain Steve Mortimer suspended, and was recalled to the New South Wales State of Origin side. He was selected in all three matches from the bench and went on to be selected in the Australian Test side for the opening match against New Zealand. Lamb came on from the bench as a replacement for Dale Shearer. Lamb got more time in the 3rd Test when he came as a replacement for the injured Wayne Pearce playing lock forward. His good form at Canterbury continued with the Bulldogs making a third successive Grand Final, once again playing Parramatta Eels. Lamb was the leading pointscorer for the season, and he would end up scoring 210 points. However, he missed a difficult penalty goal attempt in the final three minutes of the 1986 Grand Final. The Eels won 4–2. Lamb was then selected to go on the Kangaroo Tour.