@Warren
You missed
this part where you can see that she blocked his punch and hits him twice instead. You need to slow it down for proper viewing, and you can also hear the sound of blcoking which is different from the sound of swinging a punch that missed. Here's the screencap:
Then she goes for the IG where Thanos grabs her arm and swings her away. You don't need higher AP to do that, just lifting strength enough to lift that character.
All in all, she landed a few good blows on Thanos, even excluding the one kick from behind. She blocked one of Thanos' punch pretty easily. Dodging =/= being weaker. All of it proves that she had an upper hand. Thanos wasn't even able to phase her while her hits were able to stagger him showing much greater effect. (Thor was out in a single headbutt while Cap was out in a single punch.)
Then she forces Thanos to make this face:
While her own face was pretty composed:
Then she took Thanos' headbutt just like she blocked one of his punches, like a boss. And proceeded to bring Thanos to his knees:
Which made Thanos realize that he can't win in a straight fight, so he used the power stone. Her face was still composed until she was surprised by Thanos using the power stone:
Finally when you take the whole fight into account, you'll realize Thanos never had an upper hand AP-wise. Carol was the dominant one from the start and continued to be till the end, except the part where she was grabbed and thrown away by Thanos which has nothing to do with AP.