Christophe Berra admits only a victory against Wales tomorrow night will keep Scotland's hopes of reaching the 2014 World Cup finals in Brazil alive.

The Wolverhampton Wanderers defender's assessment is blunt, but then there is little point in trying to avoid the truth of what has become a critical tie, even this early in the qualifying campaign.

Already, Croatia, Serbia and Belgium look capable of breaking away at the top of Group A, at least from the losers of tomorrow night's game in Cardiff. Although a trip to Wales should never be underestimated, Berra believes that if Scotland are to be credible contenders for qualifying, the team needs to be able to win games like these away from home.

"Let's be honest, Wales are a team that we're fancied to beat but they'll be saying the same," he said. "They're the kind of team you're trying to take a minimum of three, four points against. You're looking to win both games. To have a realistic chance, that's what you've got to do. That's what you've got to do to win the league if you're a Man Utd or a Man City – you have to win those tough games away from home.

"We know it's a massive game against Wales and neither team can afford to get beat. The pressure's maybe slightly more on them being at home. But to have a good chance of qualifying from this group we need to get a victory. There's a lot of hope in the nation but we've got a good group of players.

"There will be pressure, not just on the manager but on the players as well. We enjoy being here and working under the manager. We like the way training is, we like the way we play. Everyone enjoys coming now, and we'll be going out to get the points."