Russia coach Oleg Romantsev admitted he would be having strong words with his players despite their 2-0 win over Tunisia in Kobe.
Russia went top of Group H with second-half goals from Egor Titov and a penalty from Valery Karpin.
But despite three points and a comfortable victory, Romantsev was uhappy with his side's performance.
"It was a good game for the fans but there will be reprimands
for my players after the game," said Romantsev, who has threatened to resign if Russia do not qualify for the second round.
Russia were largely in control of the goalless first half but Tunisia had several promising moments.
And despite a series of threatening build-ups, Russia were unable to convert a chance until the 59th minute when Titov struck with a long-range shot.
"I'm dissatisfied with the way we played in our penalty area
and in their penalty area," said Romantsev.
"We cannot allow
our opponents to create so many chances and we created chances
ourselves but did not finish them off.
Russia's goal seemed to steady Romantsev's side and they went 2-0 up within four minutes.
Substitute Dmitry Sychev was chopped down in the box by Rahdi Jaidi and Valery Karpin stepped up to convert from the spot.
Tunisia were undeterred and pressed through playmaker Ziad Jaziri but further chances went begging at both ends.
"We have work to do in both penalty areas," said Romantsev.
Russian goalscorer Karpin, though, insisted there were mitigating factors for his side's display.
"The humidity during the match was tough to bear," he said.
"Now I don't want to think about the next match - I just need a break."
Russia lead the group from Belgium and co-hosts Japan, who drew their opener 2-2, with Tunisia in last place.