This one's pretty legendary - Kotare Chief's Auckland Cup in 1987. 2 miles? No sweat. Leads by 25-30 at one point, and not only holds on but breaks the track record. And I may be wrong, but I think that 3:16.63 has only been beaten once since.
http://www.youtube.com/watch?v=mxvnSpVDJdY
Hardly 'contested', admittedly...