Key playmaker Alexander Mostovoi remains an injury doubt for Russia ahead of their opening group game in Kobe.
The Celta Vigo midfielder is facing a race against time to recover from the hamstring problem he picked up in a friendly against Yugoslavia.
And coach Oleg Romantsev will wait until the morning of the match before deciding whether or not to include him.
"I'm getting better every day," Mostovoi said.
"I've been practising with the rest of the team for two days already, but I don't know if I will play tomorrow or not."
The 33-year-old is so central to Russia's hopes of reaching the second round that Romantsev is likely to risk him.
If Mostovoi fails to make it, Russia's hopes will hinge on the form of their other key players, fellow midfielder Igor Semshov and young strikers Dmitri Sychov and Alexander Kerzhakov.
Bordeaux midfielder Alexei Smertin and defender Vyacheslav Dayev both missed last week's final warm-up against Japanese club side Shimizu S-Pulse.
Tunisia coach Ammar Souyah has a string of injury worries ahead of Wednesday's match.
The most significant of these concerns star midfielder Oussama Sallami, who twisted a knee in a friendly against J-League outfit Oita Trinita.
His absence would compound the difficulties caused by other unavailabilities.
Defender Emir M'kademi has already been ruled out with a muscle problem.
Veteran goalkeeper and former skipper Chokri El Ouaer has retired and playmaker Skander Souyah has been suspended for doping.
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MATCH PREVIEW STATISTICS
F = Friendly International
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FIXTURE HISTORY
DATE COMP MATCH RESULT
20 Mar 1977 F Tunisia 0-3 Soviet U
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MATCH SHORTS
Russia will take part in the World Cup for the ninth time in history. The former Soviet Union participated six times and Russia twice.
Tunisia took part in the World Cup twice; in 1978 and 1998.
The best result Russia ever achieved at the World Cup was the fourth place the former Soviet Union reached in 1966.
Tunisia have never reached the second round of the World Cup.
Tunisia have won one match in their history of the World Cup; in 1978 they beat Mexico 3-1 in the first match they ever played at the World Cup.
Tunisia and Russia have met once before; on 20 March 1977, the former Soviet Union beat Tunisia in a friendly match: 3-0.
Active Russian players with the most World Cup experience are Valery Karpin and Yuri Nikiforov, who both played three matches in 1994.
Tunisia have nine players in their squad who also played at the World Cup 1998.
Both Tunisia and Russia have had quite an unsuccessful run up to the World Cup; neither team has won a single match in 2002.
Russia have scored at least one goal in their last seventeen competitive matches; the last time they could not find the target was on 14 October 1998, when they lost 1-0 to Iceland in a qualification match for Euro 2000.