Some matches can drag a long, long time if playing against competent players and solid decks. A few days ago I was in a match that lasted close to an hour. We were behind most of the match but after fending off countless attacks and resetting the board state a few times over we managed to claw out a win.
In Duels 2014 I can recall 3 games that we won because our opponents decked themselves before we did, mind you there was no mill involved. LOL The games went from intense to painful on the last 15 cards on the deck.