First games always seem to run long. My first was wizard versus priestess... It took over five hours. They got faster each time after that, though the priestess can really draw things out if the player chooses to. The wizard isn't quite as turtle prone, but maintaining control can also slow things down. If you haven't tried it yet, play a beastmaster vs warlock. I'd be surprised if you break 90 minutes in your second ever duel. That matchup here can end in 30-40 now for us.
As Drealin said, once you start to focus your play on killing the enemy Mage, the only way to win, your games will speed up considerably. My first several duels both players got caught up in massive creature battles. It is funny now, but when we were learning and playing with the basic starter books we'd get so caught up in the creature battles that we'd run out of spells!