Yes the fight with Iron Man was believable, but his fight with Spider-Man? I thought was unbelievably far fetched. When Spider-Man had Cap webbed and they both pulled on those webs tug of war style, Cap won. That is impossible. The sheer amount of force tugging on Spider-Man's arms while webslinging through the air is by itself way more force than Cap could pull off. In reality caps arms would have came right off of his body. If caps was that strong he never would have been phased by that high fall. He'd have landed on his feet like Spider-Man.