Scotland's World Cup group has been "blown wide open" by Japan's shock win over South Africa, lock Grant Gilchrist claims.

The Brave Blossoms left rugby fans across the globe stunned with Saturday's thrilling last-gasp 34-32 triumph over the Springboks.

The result - dubbed the biggest upset in rugby history - ended Japan's 24-year wait since their last victory at a World Cup finals and handed the two-time former champions a nightmare start.

But Edinburgh forward Gilchrist also believes it has now given the other teams in Pool B - Scotland, Samoa and the United States - real belief that they can edge out the South Africans in the battle for the two quarter-final slots.

Scotland will get their tournament under way on Wednesday at Gloucester's Kingsholm Stadium and will be praying they do not become the latest victim of Eddie Jones' side.

Gilchrist - who has been picked ahead of giant team-mate Richie Gray to start in the second row - said: "We have always had a lot of respect for Japan. We've been looking at them for a long time and could always see they were a top side.

"They showed that on Saturday and in terms of the group, it's blown it wide open.

"It changes the dynamic of the group. Looking from the outside you'd have expected South Africa to have won their first two games before facing us.

"But even the likes of Samoa, now that they have a win under their belt over the US, will be looking at South Africa and saying, 'We want to beat them as well'.

"We want to qualify and while the Japan result doesn't change what we want to do, it does change the mindsets of the other teams who thought South Africa would roll over all their games."

Japan - who have now leapfrogged the 12th-placed Scots in World Rugby's official rankings after moving up to 11th - shocked the Springboks with their cavalier approach.

Twice they turned down the chance to claim a draw with stoppage-time penalties in favour of charging after the winning try which Karne Hesketh eventually scored to send the Brighton Community Stadium into raptures.

Dark Blues head coach Vern Cotter, though, believes the Japanese only showed 80 per cent of their capabilities against the Springboks and Gilchrist warned that even if Scotland knew exactly what was contained in Jones' game-plan, that might not be enough to save his side.

"It's one thing knowing what's coming and it's another thing trying to stop it," he said. "Japan have proven they are a top Test side with a lot of dangerous players so we need to be on top of our game, otherwise we'll struggle."

Cotter has decided not to take any risks against Japan after naming a near full-strength line-up.

Scrum-half Greig Laidlaw will skipper the Dark Blues at the home of his club side, while Finn Russell will be expected to set a rapid tempo against the physical Japanese outfit from stand-off.

Mark Bennett and Matt Scott form the midfield partnership, with Stuart Hogg also given the nod after shaking off an ankle knock. Wing Sean Lamont - partnered by Tommy Seymour - will nudge closer to his century of caps when he makes his 98th international appearance.,

The all-Edinburgh front row of Alasdair Dickinson, WP Nel and hooker Ross Ford lead a pack that also features Gilchrist and Jonny Gray in the second row, with Ryan Wilson, John Hardie and number 8 David Denton named in the back row.

South African-born Josh Strauss - who only qualified for Scotland through residency rules last week - could make his Test debut off the bench.

The Scots have won all four of their previous clashes against Japan but Cotter insists no-one is taking the next meeting for granted.

He said: "I think the (Japan-South Africa) result hit home. Certainly there is no complacency there. Our squad is a humble group. It's not one that gets ahead of themselves.

"It gave us an additional focus because they didn't just compete - they won. As coaches we didn't get much sleep after the game.

"There's only four days between their first two games but we expect them to be just as ferocious, just as well organised and just as driven against us as they were against the Springboks."