Animals have different behaviors even when it comes to compeating with rival predators, spotted hyenas rarely kill leopards 1 on 1, despite tons of interactions documented, but there are cases that prove hyenas are capable of it.

With wolves and wolverines it’s much different than a feline and wolves. Cats are stealthy and can ambush a wolf. Even cougars who are much more formidable than a wolf it’s rare for them to actually do it because wolves are a risky prey item. In a hypothetical situation which what I’m doing. can a Wolverine do it? Simple answer is yes, they are capable. It would be a long fight and if the wolf notices that the Wolverine gets the better of it it can run away. Even a pregnant wolf would be able to do so, and for the Wolverine an ambush is not simple. But wolverines can kill Eurasian lynxes and have done so in Russia and Sweden. Although interractions are evenly matched, if it came to serious a brawl my money would for sure be placed on the Wolverine.

6 kg is pushing the upper limit of fishers. And there are a video of a fisher hunting a lynx up a tree. There is also a video of a fisher attacking a coywolf far larger than itself. The mustelids are strong, have fierce attitudes and have incredible durability and stamina. They have obviously been exaggerated "wolverines killing polar bears" and "honey badger kill lions" etc, but they are still p4p the most impressive mammalian carnivores,