Portugal were forced to settle for a play-off place once again when they finished second behind Russia in Group F.
Sweden, runners-up in Group C, were drawn to face Paulo Bento's side over two legs in what has been billed as duel between captains Cristiano Ronaldo and Zlatan Ibrahimovic.
Portugal qualified for the 2010 World Cup via the play-offs and they also sealed a spot at last year's European Championship via the same route.
And Pepe expects Sweden to provide a stern test, with the Real Madrid man refusing to believe Portugal should be considered favourites.
He said: "We have to face this situation with as much transparency as possible so we can qualify for the World Cup.
"What we try to do in these two games and we have to be very smart to be able to achieve the qualification. This game against Sweden will be extremely difficult for us, we have to live up to in order to get a positive result.
"They are try to pass the pressure to Portugal but I think there is a 50 per cent chance for each side. Over two games, we have to be good to get the qualification."
Pepe also also hailed Ronaldo, his team-mate for club and country, as the best player on the planet and hopes the prolific forward is rewarded with the Ballon d'Or.
He said: "Ronaldo is, from my point of view, the best in the world. His numbers (goalscoring record) are unthinkable and therefore I think at this point there is no comparison.
"I hope that this year he is the winner."
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