Sweden vs. Portugal 2nd Leg
"We have an English referee now so we can probably go in a bit harder," said Sunderland player Larsson.
"I do not think he is going to fall for the same tricks so easily."
Cristiano Ronaldo headed Portugal's late winner in the first leg, but the Real Madrid forward also won a number of free-kicks.
"Howard Webb is used to refereeing where the game is a little more physical," added Larsson. "He's a great referee, too, which is important for such a big game."
Portugal coach Paulo Bento believes his team will have to overcome "enormous difficulties" as they try to hold on to their slender advantage.
"We'll have to be tactically and mentally prepared because we'll face 90 minutes of suffering to reach our objective," said Bento.
"I think it will be a similar situation to our own, when we try to stop the organisation of Sweden and us having in mind of course trying to stop [Sweden forward Zlatan] Ibrahimovic."