Hulk is clearly a powerhouse but he's an impulsive rage monster. Thor on the other hand is level headed and can think in terms of strategy, so he has an advantage and that makes him a better fighter. So because of that he can deal with the Hulk. We saw him dodging, counter-attacking, trying to reason with him but at one point he let loose and they both go at it. So to me, Hulk was the Hulk as in punch, punch, smash, smash. Thor was more skilled and while there were lots of times the Hulk bested him, I believe he came out on top because of this.
Now when Thor let loose and started lightening up, you could feel the tide changing. Hulk was pummeling the **** out of Thor but then he got up and lighted up and blam! Then they run towards each other like in the trailer and Hulk took a mean lightening uppercut and was sent away. The force of the blast sent Thor away as well and the crowd was then chanting "Lord of Thunder" instead of "Hulk". At that moment, Thor was getting on top. The crowd noticed it, chanted his name, and the Grandmaster look worried AF. Then he activated Thor's disk, but NOT TO END the fight in a draw. The fight doesn't end there. It weakens Thor, THEN Hulk does a massive super jump to meteor down on a incapacitated Thor. As Hulk descends with his fist on Thor we have a POV shot of Thor looking up at Hulk and slowly raising his hand ready to block to punch. Thor still has some fight in him. But then he fainted. Cut to Thor's wounds being tended to. The Grandmaster cheated to give Hulk, his champion, the win. He didn't end the fight to call it a draw. He incapacitated Thor so Hulk could finish him. Which he did. And Thor even complained to Hulk afterwards that this was some major bull.
Could Hulk deal lightning Thor? Maybe, I think if he got angrier as Thor was getting more juiced up he might. But in the movie, Grandmaster cheated to give his champion a victory.