Six Nations: Martyn Williams on England's win over Wales

Billy Vunipola is tackled by Taulupe Faletau and Rhys Webb

The Twickenham meeting between childhood friends, and rival number eights, Taulupe Faletau of Wales and Billy Vunipola of England was one of the most eagerly-awaited Six Nations showdowns this season.

England came out on top with a 25-21 victory - but who won the back-row battle and who should wear the British and Irish Lions number eight jersey next summer?

Former Wales captain, BBC Sport pundit and 100-cap international Martyn Williams assesses the Faletau-Vunipola showdown.

Vunipola v Faletau - who came out on top?

I thought they both played really, really well.

England's Vunipola has probably been the player of the tournament and he did what he did best on Saturday, particularly early on.

He made a few good carries - maybe not the eye-catching 20-30 metre ones we saw against Ireland - but he was breaking tackles and got England on to the front foot along with James Haskell, Chris Robshaw and Maro Itoje.

Faletau got better the more the game went on, like most of his team-mates did. For the first 30 minutes he was pretty quiet, but towards the end of the match he showed what a quality player he is.

Vunipola focus caused Wales problems out wide

While Vunipola didn't make his usual big carries, it was still taking two or three men to stop him, which made it so difficult for the rest of the Wales team to defend other areas of the pitch.

Normally tackles are made one-on-one, but Wales had a game plan to focus on him with two or three men attempting to bring him down.

This however, meant the Welsh defence got quite narrow and made it a lot easier to attack out wide. The space that was left was exploited well by England.

That is the danger of playing against someone of Vunipola's ability. It is easy to end up focusing too much on that one guy which leaves weaknesses in other areas. England's number eight was sucking in two or three defenders allowing fly-half George Ford the freedom to attack that little bit wider.

Wales' line speed early on was affected by how narrow they got. There weren't coming off the blocks in the way you would normally expect of a side prepared by defence coach Shaun Edwards. They were on their heels and too narrow and it created that space outside.

What should Wales have done with Vunipola?

It's the old adage of getting to him early. You've got to go low and bring him down which allows you to get over him and try to steal the ball. But with such a big man and such an explosive player it is a lot easier said than done.

Next Saturday, France must not concentrate too much on him as they will fall into the same trap Wales did. They've also got to make their one-on-one tackles, which the Welsh failed to do in the first half of Saturday's game.

Two players at the top of their game

Vunipola has come of age in this Six Nations. He enjoys playing under Eddie Jones and has been given freedom.

He is such a natural footballer with great ball skills, and superb footwork for a big man.

Everyone thinks he is just a battering ram, however, if you watch him use his feet you can see why he is so elusive and hard to stop. He is not just a carrying number eight, he has worked so hard on his fitness and it is really paying off for him.

He has been immense and my player of the tournament without any shadow of a doubt.

I think Taulupe is a more rounded and complete number eight at the moment, but every game sees Vunipola get up to his level.

Faletau has easily been Wales' best player in this Six Nations. His consistency is incredible - he comes top of every chart.

I played against him for the Barbarians when he won his first cap for Wales and you just knew then how special he was. He plays every game for Wales - he is never injured and his work rate is phenomenal.

For Vunipola, that is the next step - look at Faletau's work rate and copy it. Some of the covering tackles he makes show what a fantastic athlete he is.

Dan Biggar and Alun Wyn Jones have got the headlines over the past 18 months but I think Faletau is now Wales' best player.

Itoje - future Lions captain

It isn't just Vunipola who has shone in this Six Nations. Maro Itoje has future British and Irish Lions captain written all over him. I know it's a big thing to put on someone but what a find England have.

For him to play so well in a game of such magnitude, up against a side full of experience, especially in the second row, was incredible. He was a shining light in what was only his third cap.

I've talked about Faletau's all-round game, but this kid was stealing line-out ball, winning penalties, carrying, tackling, basically doing everything. He was phenomenal for such a young man.

As for his best position - it is such an interesting question. He looks OK at four so far! Maybe in the future I'd like to see him at six (blind-side flanker) with his athleticism and carrying ability. He would be so explosive out in the loose, however, at the moment Chris Robshaw is playing out of his skin.

It's certainly a nice little quandary for Eddie Jones and Steve Borthwick to have.

Redemption-man Robshaw

Former England captain Robshaw deserves so much credit for the way he has bounced back after what was such a dismal World Cup.

He must have been in such a dark place. I can't think of a rugby player that has come in for so much criticism and had a spotlight so firmly trained on him.

Many a weaker man would have buckled but for him to show such strength of character by playing in a different position without the captaincy speaks volumes. I always thought he was a number six and he is playing so well there.

The England back row as a whole has been brilliant as a unit, despite a not having a true number seven. They work really, really well, not just defensively, but also going forward.

Lions number eight?

It's an area that the British and Irish Lions have always had a lot of strength in, and at the moment they are blessed across the back row.

Right now, I'd go with Faletau starting at eight, with Vunipola's explosiveness being used off the bench in the last 25 minutes. That for me is not far off the perfect scenario for a coach. I know Vunipola has been the player of the tournament but if a Lions Test was this summer I would start the Welshman.

The Lions back row looks frighteningly strong for next year.

Martyn Williams was talking to BBC Sport's Paul Birch