Billy Vunipola feels his best is yet to come

England back-row Billy Vunipola feels he can become an even better player if he plays to his full potential.

Vunipola is currently enjoying a dream run after being part of Aviva Premiership and European Champions Cup winning Saracens team in the previous season.

He was also an integral part of England's 3-0 series victory in Australia and has won three man of the match awards in his last 12 games which his team ended victorious in 10 of it.

Earlier, the 23-year-old revealed that England coach Eddie Jones had challenged him to become the best number-eight in the world and Vunipola believes he still has a lot of scope for improvement.

"I'd say I'm 50 per cent," Vunipola told Press Association Sport.

"I can add another 50 definitely. There's a lot left. I feel like I can get way better than I am at the moment.

"I want to be the best. I was too scared to say it because I'm not anywhere near that level yet but Eddie laid down the challenge and it's there on paper now.

"I don't want to be an average rugby player. I don't want to be just a good Premiership player, who was OK at international level. I want to be very, very good at both."

Ever since Jones took over from Stuart Lancaster, England are on an unbeaten streak, which saw them climb to the second position in the World Rugby Rankings with only the All Blacks above them. The Saracens number-eight believes England should not be overhauled by the defeats in the process of building a platform to become the best team in the world.

"It's inevitable we're going to have a dip at some point, that's human nature, but it's important then that we stay close as a group and don't get drawn into over-reactions," Vunipola said.

"The All Blacks have lost games but they never over-react. They stay true to themselves and they've stayed at that level for such a long period. It's not one or two years but eight, nine, 10 years.

"That's what we're pushing towards. It's a big challenge but one we're excited to face."