In September 1942 three airplanes carrying British soldiers crossed the border into Greece, this event symbolized the start of Operation Harling which was part of the special operations executive’s unconventional warfare campaign. The operation culminated in the destruction of the Gorgopotamos viaduct. The Operation is described as one of the most spectacular sabotage operations in axis occupied Greece and include the support of two local guerrilla. This study uses McRavens theory of relative superiority to help analyse how success was achieved in operation Harling through a qualitative text study. The purpose of the study is to examine the phenomenon of unconventional warfare through a single case study with McRavens theory of special operations. Furthermore, the study also investigates the explanatory power of McRavens theory. The results show that three out of McRavens six principles were present in the operation, simplicity, security and surprise. The theory states that all six principles must be accounted for to achieve relative superiority, therefore the success in Operation Harling cannot be solely explained by McRavens theory. Thus, the result indicates that further research must be concluded to shed light on the concept of unconventional warfare.