From the viewpoint of a retired futbol ref.... absolutely the correct call on the red. The Pitt player had a clear path to the goal and the trip kept him from having an opportunity to score. The only question I had was the position of the keeper - if he was clearly going to collect the ball, then no red. It was close, but in that situation, you can't assume the keeper would have gotten to it before the striker. The Marshall player clearly clipped the striker's left foot and the ref correctly ruled that foul occurred outside of the box. I've been around floppers enough to know that if the striker was going to flop, he would have waited one more step to be in the box. Plus, we look at arm flailing, etc. to indicate flopping - there was none of that.
Good game to win, and still allow Chris G. things to work on.