I found that part rather chilling, actually, as it made a rather important point. Tony went absolutely gang-busters against Thanos, pulled out all of the stops, used everything he had, had the upper hand due to keeping Thanos off-balance the whole time, pulled some pretty spectacular moves out of his bag of tricks with the nano-machines....
[Thanos] *checks tiny scratch on his cheek* All that for a drop of blood.
I felt that and the Hulk beatdown were the two times in the movie that it really managed to capture just how overpowering Thanos is compared to the heroes.