SAM Warburton has warned there can be no easing up when Wales target a flying start to their World Cup campaign against minnows Uruguay on Sunday.

The South Americans' last World Cup experience realised a nightmare 111-13 drubbing by eventual tournament winners England in Brisbane 12 years ago.

And while they appear to be a considerably improved outfit in recent seasons, Uruguay's Millennium Stadium visit promises to be little more than a prolonged damage-limitation exercise.

Host nation and fellow tournament heavyweights England are looming for Wales at Twickenham next week - head coach Warren Gatland has held back skipper Warburton's fellow star players like George North, Jamie Roberts, Dan Bigger, Gethin Jenkins, Alun-Wyn Jones and Taulupe Faletau until then - but in the meantime it is a case of one job at a time.

"We have to be respectful to Uruguay, who will be more organised than in the past," Warburton said.

"They've had a month together, so they will be more organised.

"It's quite a tricky situation. The main thing is you want to get a win and if you're in a bonus point situation, great, and after that we will be foot down for 80 minutes.

"In no game will we ease up, as you don't want to look back in four weeks and wish you had pushed a bit harder."

With Australia and Fiji also lurking in Wales' pool and just two teams progressing to the quarter-finals, at least one major casualty is guaranteed before the knockout phase.

"It wouldn't surprise me if there is an upset in there," Warburton said. "There are some difficult turnarounds for some teams.

"I wouldn't underestimate any team. Fiji are a different team from four years ago - they are going to be a real threat in the group.

"I really don't know what is going to happen. It only takes one fixture to turn it on its head."

Wales head coach Warren Gatland's line-up for the Uruguay game sees opportunities for players such as centre Cory Allen, fly-half Rhys Priestland, scrum-half Gareth Davies and number eight James King, while full-back Liam Williams and prop Samson Lee make returns following long injury lay-offs.

"I was at the (World Cup) draw and I remember thinking our pool was all people would talk about for three years, but now it seems real," Warburton said.

"This week in particular, with all the World Cup banners around the hotel, it feels like it's time again.

"It is really exciting and a different feel to a Six Nations campaign or the autumn Tests. The matches will be rolling in thick and fast."

Gatland said: "I think we have got to put all our focus into these first two games (against Uruguay and England).

"We have got a short turnaround to next week. We travel to London on Monday and have a (World Cup) cap presentation, and the boys have got Tuesday off so it's a short training week.

"So we have mixed and matched a little bit this week in terms of the way we have done things, Some of the focus has been on England and the latter part of the week has all been on Uruguay."