Portugal go into the match leading 1-0 from the first leg - Ronaldo scored the only goal with a diving header - but Larsson believes the appointment of an English referee could be crucial to Sweden's hopes of making the finals in Brazil next summer.
Ronaldo won a number of free-kicks during the first leg but Sunderland midfielder Larsson told media in Sweden: "We have an English referee now so we can probably go in a bit harder.
"I do not think he is going to fall for the same tricks so easily.
"Howard Webb is used to refereeing where the game is a little more physical. He's a great referee, too, which is important for such a big game."
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