Hamamatsu - Scotland are targeting a bonus-point victory, and nothing less, over Russia on Wednesday to set up a Pool A showdown with hosts Japan for a spot in the quarter-finals.
Coach Gregor Townsend made wholesale changes to the team that beat Samoa 34-0 last week, bringing in 14 players as he attempts to manage his 31-strong squad with only a four-day turnover before the game against Japan, in Yokohama on Sunday.
"We've got two big games coming up," said Townsend. "We've had a long rest into this game."
Russia, ranked 20th in the world, have suffered three defeats in their three pool games, going down to Japan (30-10), Samoa (34-9) and Ireland (35-0) to end any slim hopes they had of progressing to the last eight.
But Townsend warned that they were expecting a tough battle in Shizuoka, highlighting Russia's strengths as their improved defence and fitness, solid scrum and territorial kicking game.
"It's their last game, they'll throw everything into this," said the ex-Scotland and British and Irish Lions fly-half.
"We're expecting as good a performance as they gave against Ireland, or better."
Scotland capitulated 27-3 in their campaign opener against Ireland but rebounded to beat Samoa 34-0 to set up these two games crucial to escaping from the pool.
And an injury-time fourth try that gifted Japan, shock 19-12 victors over Ireland, a bonus point against Samoa set up the do-or-die showdown against the Scots, should the latter not mess up against Russia.
"We have to win our next two games to qualify," was Townsend's blunt assessment. "If we don't get a bonus-point win, it's all the more difficult... If we don't get a win, we're out of the tournament."
Scotland's openside flanker Fraser Brown said there were "no two bigger games with what's on the line".
"You're playing for a place in the knock-out stage of the World Cup."
Brown said the turnaround would be tough between games, but insisted the focus was solely on Russia.
"You can't hide away from the fact that it's difficult to play two Test matches in four days," said Brown.
"But you have to get on with it, get your head in it, get ready for Russia and as soon as that game against Russia is finished, we'll have to get prepared properly in the time we have for Japan."
Meanwhile, Russia's Welsh coach Lyn Jones has made four changes from the team that battled well despite defeat by Ireland.
"We appreciate how difficult a victory would be, but Scottish people are not different from everybody else," Jones said.
"They are human beings who are fallible when put under pressure. It's for us just to bring a little bit extra to our game."
Russia captain Vasily Artemyev, who has become a cult figure in Japan thanks to his bushy moustache, never-say-die attitude and thick Irish accent - the latter thanks to being schooled in Ireland, said Scotland were similar to the Irish, with dominant half-backs who look to control the game.
"We will try to do better as we improve with every game at this tournament," the full-back said.
"We'll try to improve more and to create problems for Scotland's defence and put their attacks under pressure."