Russia travel to Portugal hoping to put speculation over manager Fabio Capello's future aside while taking a huge stride towards World Cup qualification.
The build-up to Russia's Group F test in Lisbon has been overshadowed by reports linking Capello with a return to club football with Paris Saint-Germain.
It is an unhelpful distraction for the group leaders, who have made a superb start to their qualifying campaign.
Russia have won all four of their matches to date to top the group by a point from Israel and Portugal, who have both played two games more.
Another victory at the Estadio da Luz would put the Russians in a commanding position.
Capello's recent remarks have not dampened the speculation over his position.
"I'm happy in Russia at the moment and I'm pleased with my life and work here," the Italian former England manager, who is midway through a two-year contract, told reporters.
"But anything is possible in this life, so never say never."
Defeat would not be too damaging for Russia, who could make up points in their rearranged game against Northern Ireland in August, but for Portugal the encounter is crucial.
After collecting just three wins from six games, Paulo Bento's side have a more urgent need for points.
A loss to Russia in Moscow and a home draw against Northern Ireland in space of four days last October are the chief reasons why the Portuguese have fallen behind.
Goalkeeper Rui Patricio, of Sporting Lisbon, said at a press conference: "There have been games when things have not gone as we wanted but we have the ability to a come back and the match with Russia is right time to do so.
"We want to win this game and ensure our presence at the World Cup.
"We're just focused on winning. That is our main goal and that is what we are preparing for at this stage."
Portugal will be without influential Real Madrid centre-back Pepe through suspension.
Patricio said: "Pepe is very important to us but whoever is in his place will be his equal.
"I have also had games without Cristiano Ronaldo and we have won."
There is another Group F match taking place, but with no bearing on the qualification positions, as Azerbaijan host Luxembourg in Baku.
Neither team have yet won a game with Azerbaijan having collected just three points and Luxembourg a mere two.