Billy Vunipola knows he has to prove himself again to England coach Eddie Jones

Vunipola has started the season with a bang.

Billy Vunipola has started the new season in impressive fashion (Mark Pain/PA) (PA Wire)

Billy Vunipola enhanced his World Cup prospects during England’s tour of Australia but the Saracens number eight insists he must sway Eddie Jones all over again as the autumn comes into view.

Vunipola has started the season with a bang, adding to his man of the match afternoon against Harlequins with an influential shift in Saturday’s dramatic comeback victory over Gloucester.

Injuries to Alex Dombrandt and Sam Simmonds ended his international exile in July and although the 29-year-old was a force in the 2-1 series victory over the Wallabies, he knows his rivals are ready to reassert themselves.

“The World Cup is obviously a goal, but my focus has to be on what’s right in front of me rather than what’s further down the line,” Vunipola said.

“I was pleased with how it went but I can be better. I can still be fitter. That’s the challenge for me. It’s an exciting challenge for me.

“I don’t think I re-established myself. I feel like I put myself in position to ask questions to be selected again, but I can only do that if I’m playing well week in week out.

“You never know what can happen, what’s around the corner, which is why it’s important to focus on day to day.

“When you fall over yourself is when you don’t focus on the hurdle that’s right in front of you.”

Vunipola admits it was the simplest of decisions to end the 10-week stand down period for players involved in the England tour period early by returning ahead of schedule against Harlequins.

“It’s a toss up for me. It’s either running without the ball or playing. What would you do?! It was an easy one for me,” he said.