Kobe - Scotland hooker Fraser Brown said the side are facing the biggest games of their life with matches against Russia and Japan in the space of five days set to determine their Rugby World Cup fate.

After a woeful 27-3 opening loss to Ireland, the Scots bounced back to beat Samoa 34-0 in Kobe on Monday in a tightly-contested Pool A.

They face minnows Russia, who play Ireland on Thursday, on October 9 before finishing the group stage against tournament hosts Japan - who stunned Ireland 19-12 last weekend - four days later.

Realistically, Scotland now need to win three successive matches at a World Cup for the first time in 20 years if they are to reach the quarter-finals.

"You have to treat the game you're playing next as if it's the biggest game of your life and the context we're in just now, there's no two bigger games with what's on the line," Brown told reporters.

"You could be playing for a place in the knockout stages of the World Cup."

A four-day turnaround between physically demanding Tests has raised questions over sporting fairness and whether squad sizes, currently limited to 31 players, need to be increased for future World Cups.

But the situation confronting Scotland is the same one Japan faced at the 2015 edition in England, where their 'Miracle of Brighton' win over South Africa was followed four days later by a 45-10 loss to the Scots in their next pool match.

"It's fair, because it's part of the competition," said Brown when asked about the short turnaround.

"We can't say it's not fair because it's us, and four years ago or last week someone else had it so it doesn't bother you. It's the way the tournament is.

"There's five-day turnarounds in the (Pro14) league, there's five-day turnarounds back home between league games and European games. You just have to deal with it."

But Brown said player welfare concerns meant officials should consider allowing larger squads at future World Cups.

"A 31-man squad leaves you open to disadvantages in your squad... You've got to take gambles (on positions) and hope that luck's going to be on your side," said the Glasgow forward.

"It does put a lot of strain on players, particularly now when we're talking about player welfare and HIAs (head injury assessments) being a massive focus for the past two or three years.

"You only have to look at other aspects of the game, predominantly the ruck, to see the risk that players are at now."