Their was a huge gulf in the standings of the two sides last term as only Zebre finished below the Dragons in the RaboDirect PRO12 table but Muller doesn't envisage similar struggles this time around.
"They're a different side from a couple of months ago. There's development with a new coaching staff in place and we won't be the only side that loses there this season," said Muller.
"They outsmarted us and they played with a lot of passion and pride. All credit to them, they deserved to win.
"Whenever you give a side like the Dragons a sniff, they won't back down. We had a great week training wise and the boys were really up for it so it definitely wasn't a lack of effort on our part."
Muller was particularly taken by the Dragons' defensive efforts as they made tackle after tackle in the closing stages after Jason Tovey's boot had seen them overturn an 8-6 half-time deficit.
Ulster attempted to lay siege to Dragons territory late on but Andrew Coombs and co always had an answer to their efforts.
The Dragons also had the upperhand at the breakdown as the likes of Nic Cudd, Jevon Groves and Lewis Evans in particular secured solid ball for the hosts and made life particularly difficult for visiting scrum-half Paul Marshall.
"Their scramble defence was outstanding. Even in the last 10 minutes when we were throwing everything at them they always seemed to have people on their feet and numbers in the defensive line," added Muller.
"They played with a huge amount of physicality and they were really good at the breakdown. They disrupted our ball and slowed it down at every breakdown. We're one of those teams who, when we don't get momentum, don't get over the advantage line or get quick ball, we struggle.
"When you play a really physical and competitive side like that, it's always going to be tough. We knew it was going to happen but we couldn't counteract it."
The Dragons travel to Scotland in Round 2 to face Edinburgh at Murrayfield on Friday night (kick off 7.45pm).