Billy Vunipola insists the renewal of his faith in God helped him reverse the slump in form that resulted in his England demotion.

The No.8 will profit from Ben Morgan's season-ending broken leg by starting Friday night's Six Nations opener against Wales at the Millennium Stadium.

Three months ago he paid for poor performances against New Zealand and South Africa by being axed from the match-day 23, giving Morgan his chance which the Gloucester back row seized to be named player of the series.

Recent outings for Saracens, especially against Munster in the Champions Cup, suggested Vunipola's blip was over and the 22-year-old credited a passage from the Bible for inspiring his return to form.

"The biggest thing for me has been my belief in God and I felt like I went away from that. I'd strayed," he said.

Billy Vunipola is set to start against Wales on Friday © Getty Images

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"A similar example is Manny Pacquiao - he had strong faith and when he went away from it, he went into gambling and things that went against his faith. He stagnated and didn't improve.

"The biggest thing for me was getting ahead of myself and not being humble enough to realise that even if I'd had a good game, I still had to work on my game.

"I read a passage [from the Bible] that said the arrogant will be humbled and the humble will be lifted up. I guess I was just humbled.

"I felt like every time I stepped on the pitch, I always performed at a level, without working on things that weren't going as well, like my ball-carrying.

"I wasn't working on things as hard as I should have been and I wasn't taking the time to analyse other teams. I was just thinking that my brute size alone would be enough for me and it wasn't.

"There are people out there who want your position and I didn't appreciate that until I got sent home. I was always moaning all the time, but now I appreciate being here and realise how lucky I am. Hopefully that will come out in my game on Friday.

"Sometimes you don't want to hear the truth but you have to. That was the biggest thing; listening to stuff that dents your ego. You have to humble yourself to be lifted again."

Vunipola has been learning from 47-cap veteran Nick Easter, his rival No.8 who has been recalled to the extended training squad at 36-years-old.

"Nick has been giving me a few points on little lines that I could do that could get me places quicker and not being so honest all the time," Vunipola said.

"I am not saying he is a cheat but he is just much cleverer than I am and he has helped me with just little points.

"He's really smart in the way he pitches his opportunities. If you want to call that short-cuts, then you can, but I think the stats speak for themselves. He has given me a different perspective.

"I asked him the other day how he has done it [playing at a high level at 36] and he came back with the answer, 'I don't over-train'. Like I said, he's a really smart guy."

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