Both Portugal and Russia lead the way in Group F, with six points from their two opening matches.
The other four countries in the group are all five points adrift already and victory in Friday's clash in Moscow could give either frontrunner a clear advantage.
But while Pepe is keen to avoid a setback he would not be too concerned should Portugal come away from Russia's Luzhniki Stadium with nothing.
"If we get out of there without defeat, it will be positive for us," the Real Madrid defender told the Portugal FA website.
"It will be a hard game, very important, but it will not decide anything."
The 29-year-old is one of three players doubtful for the clash with a thigh strain, while star striker Cristiano Ronaldo is suffering from a shoulder strain and midfielder Raul Meireles was injured in Thursday's training session.
Head coach Paulo Bento told fifa.com: "Raul injured himself today [Thursday], while Ronaldo and Pepe had their first training of the week, and we'll take a decision (on their availability to play) tomorrow [Friday]."
Russia boss Fabio Capello is relishing the clash although he was quick to avoid labelling Friday's match as a must-win.
"We should not be calling this match a decider," said the Italian. "But we have all the incentive - we should be ready to win a big match."
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The former England coach has rung the changes with Arsenal forward Andrei Arshavin, Reading striker Pavel Pogrebnyak and former Tottenham attacker Roman Pavlyuchenko all left out of the squad for the clashes with Portugal and Azerbaijan.
Elsewhere in Group F, Israel coach Eli Guttman has courted controversy for jettisoning Yossi Benayoun from his squad as he bids to get his team's qualifying campaign back on track.
Israel play a double header against Luxembourg, away on Fridaywith the return leg on Tuesday.
Former Arsenal and Chelsea midfielder Benayoun is one of the nation's most recognised players with 90 caps in 14 years but an unrepentant Guttman is looking for a response from Israel, who - like Friday's opponents - have just one point from two games.
A 4-0 home defeat by Russia left Guttman furious and the veteran coach is demanding improvement.
"We left our honour on the pitch in Ramat Gan - both in the result and in our performance - and we're going to the games against Luxembourg to restore that honour," the 54-year-old told Israel's oldest daily newspaper Haaretz.
"The players got the message and they're fully motivated to prove they deserve to be here.
"I want to see a team playing close together that knows when to press, that moves the ball, that creates scoring situations, that plays modern soccer and plays methodically rather than haphazardly.
"One of my insights is that there is no substitute for playing time, and that includes everybody. And it has nothing to do with whether he's called Yossi, Tal (Ben Haim), Itay (Shechter) or Ben (Sahar).
"Benayoun is carved into the pages of history as one of the greatest players in Israeli soccer. I paid my respects to him and called him so he would hear it straight from me."