i would even argue that they don't "fight" great whites. orcas are faster, larger, and significantly more intelligent than great white sharks. it seems it is an easy enough kill for the pods that know how to hunt them. in fact, great whites off the coast of south africa have been known to leave the area when orcas arrive. that's right: great whites are seemingly afraid of orcas.
it is sad to me humans don't understand them more and still capture and enslave them for entertainment. we also are wreaking havoc in their ecosystems and food sources. they showcase intelligence i am not aware of in any other animal besides humans.
for example, there is a technique they use such that they trick prey that they are leaving. normally, mammal hunting orcas stop vocalizing when hunting. so by leaving the area and vocalizing after an unsuccessful hunt, they relax their prey by signaling they've given up. however, they have communicated to each other to leave a single orca behind that stays silent to catch the prey once it relaxes. then the rest of the pod comes back to share.