It was just lightning strikes, and not even particularly powerful ones compared to what he has done before.Its not like he could do some huge world spanning size lightning strike or godblast with weaklings like Hyperion and Marvel there (cap obviously would have tanked it).
And its pretty obvious Thor hurt Thanos with the hammer strike seeing as he as waiting for it and it still knocked him down. Thanos doesent say ouch.
Why I find fights like this kinda boring with people like Thor amd Hulk in them. They have to hold back the whole time so they dont destroy the planet. Speaking of that. Why the **** didnt Thanos just destroy the planet Earth? He could do it with a single punch.
Thanos still wins this fight. Thor is my boy but Thanos is simply above him. He has always been above him and Hulk and SS. Thats just the way it is.