How was Thor able to defeat Thanos with the Stormbreaker?
There are multiple reasons why Thor was able to (almost) defeat Thanos with Stormbreaker .
The first reason was stated when Thor was making his weapon on Nidavellir . This occurs when Eitri is talking to Thor about the weapon and says ‘A king's weapon. Meant to be the greatest in Asgard. In theory, it could even summon the Bifrost.' This already tells us that it is more powerful than Mjolnir.
The element of surprise.
First of all Thor truly did not defeated Thanos but it did make Thanos turned to plight for some time until it snapped out!
Talking about Stormbreaker,it is the most high ranked weapon and it is indestructible unlike Mjioner,Ichi ( Gaint Dwarf that made that weapon) itself said it is weapon of kings of Asgard and its power is unmatchable. In other words it is unstopable weapon and we saw Thor destroying whole alien ships with just single blast from storm breaker and even power of infinuty stones could not stop it making it most fierced weapon avengers ever had!
hope this helps!
It breaks my heart to say this.
I love Marvel. Infinity War is the best movie I've ever seen. I cried.
But why he was able to stab him? Plot hole. Lazy writing.
I feel horrible just typing that but it's true.
The Infinity Gauntlet when all six gems and united, grants unbridled power. Omnipotence. Thanos mere thoughts would become reality. Nothing cab touch him. He is totally omnipotent. Literally Thor wouldn't even be able to show up if Thanos didn't want him to. Short of God...nobody was more powerful than Thanos.
They ignored all that and a big hammer ignored omnipotence. Whatever. He still won.
You should have gone for the head...*snap*.
I'd say this was mainly due to the element of surprise, and a bit of disbelief.
At this point in the film, Thanos is the most powerful being in the universe, and he'd already made sure no one could forge a weapon to destroy him (by killing all the dwarves but one and extinguishing their forge). To Thanos, Thor is just another minor annoyance to swat away before completing his ultimate plan. By the time he realizes that Stormbreaker is no ordinary axe, it's too late to change tactics.
Thanos doesn't seem to be the smartest villain in the MCU, nor the fastest. There's no Infinity Stone that increases reflexes, or makes you smarter.
Thor didn't defeat Thanos with Stormbreaker, he injured him grievously in his chest with the bladed part of his weapon. Thor wanted Thanos to know who it was that was about to kill him for what he had done to his people, but Thanos implemented the Infinity Gauntlet before Thor could finish what he had started.