We report a presumed damage to the left superior rectus (SR) muscle following a dog bite injury that resulted in a marked weakness of elevation and vertical diplopia. A 30-year-old male presented in October 2010 following a dog bite around his left superotemporal orbit. An ophthalmic examination was unremarkable. The patient immediately complained of vertical diplopia, which did not settle during a period of observation lasting approximately 9 months following the attack. An orthoptist examination confirmed a marked restriction of upgaze. A diagnosis of isolated SR injury, secondary to the dog bite, was suspected. A left Knapp procedure was performed. The surgery was uneventful with scar tissue found around the SR. Three months following his surgery, the patient was orthophoric in both primary positions and in the downgaze with a residual 20-prism dioptre hypotropia in the upgaze. Our patient was unusual in that the bite weakened the SR in isolation. We also show the successful management of this novel case using a simple Knapp procedure.