Someone correct please if I'm wrong...
Isn't Thanos the better fighter/more skilled fighter? If this is a fight where each just stands and takes each others blows, then yes I lean towards the Hulk.
But, the thread says H2H. I see Thanos parrying and countering a lot of these punches thrown by Hulk for an easy KO. Now, if Thanos is ineffective or takes too long, well then he's gonna experience some issues.