|World Cup Pool A: England v Wales|
|Venue: Twickenham Date: 26 September Kick-off: 20:00 BST|
|Coverage: Live on BBC Radio 5 live and sports extra, BBC local radio, plus live text commentary on every match on the BBC Sport website|
|Further coverage: BBC Radio Wales, BBC Radio Cymru and BBC Local Radio|
Prop Tomas Francis hopes the "dark" days of Wales' July training camp in Qatar can help lead to a World Cup win over England on Saturday.
The 20-stone tight-head, 23, won Wales selection after impressing with Exeter.
And having been told by veteran Gethin Jenkins not to be "lazy" at scrums, Francis is relishing the big stage.
"Gethin's told me not to be lazy, to scrummage every scrum, and he will look after me around the pitch," said Francis.
The York-born player, who is qualified to play for Wales via his Abercrave-born grandmother Eirlys, will win only his fourth cap when he lines up against England, but the former Doncaster and London Scottish player says he is becoming accustomed to the demands of Test rugby.
"International rugby is different from the Premiership and I've had to get used to that," he said.
"It was a shock to the system when I first joined the squad and there were some dark days during the training camp in Qatar.
"The rest of the boys got me through it. No-one wanted to drop out and you thrive in that environment."
Even so, Francis says he still cannot believe he is actually involved in the World Cup.
"My conditioning and fitness have come on massively since I've been with Wales," he said. "My impact around the pitch has come on a lot and I have worked on my scrummaging.
"In the Premiership, you can switch off in the scrum and you can get through it if you recover late. If you're not there the whole time in a Test you will know, and it will show with a penalty against you."
Francis hopes to do well enough against England loose-head Joe Marler to give 116-times capped Jenkins, 34, the chance to make his mark on the other side of the scrum against Dan Cole.
"I played against Joe Marler once early last season when Exeter beat Harlequins," said Francis.
"It went all right, but Quins didn't have the best scrummaging pack then. He has a great England pack around him now."
While Francis and his team-mates wait for Saturday night's encounter, former Wales lock Ian Gough believes England are "fragile".
Gough, who won 64 Wales caps, said: "Typical England, they're very sure of themselves at times.
"Confidence and arrogance are close, but I think you could hide it [fragility] a bit by being like that, and I think Wales can do a job."
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But Gough, 38, believes Wales' Six Nations title-securing 30-3 thrashing of England in 2013 demonstrated the vulnerability of Stuart Lancaster's side.
"They capitulated that day. I'm not saying that will happen, but I think they're on a bit of sand," he said.
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