The Germany international admitted his side had to work hard to claim what he feels was a deserved 2-1 win over Wolfsburg
The Bavarians got their Bundesliga campaign off to a winning start thanks to goals from the Germany international and Arjen Robben either side of half-time, though Ivica Olic's strike ensured a nervy ending.
However, Muller believes that the right team won on the night but conceded that there was plenty of tension in the Bayern camp.
"[Bayern's World Cup winners] tried to play like we did in the final," he is quoted as saying by the Bundesliga's official website.
"It wasn't that different - there was plenty of tension but I think the best team won. We pulled together and managed to grit our teeth for the last 10 minutes.
"You have to do that sometimes."
Meanwhile, Robben has admitted that his side were left a little short of fitness due to the World Cup and reserved special praise for Gianluca Gaudino, who shone on his Bundesliga debut.
"Opening matches are always a bit strange. We didn't have much preparation because of the World Cup, not much training and lots of injuries, but we shouldn't be making excuses.
"The three points are the most important thing. Big compliment to the lads, especially young Gaudino. I'm very proud of him."