Jeremy Guscott’s verdict: Fitness tells and so do Jonathan Joseph’s twinkle toes

England's victory over Wales in Cardiff was about energy, discipline and defence, and they proved that when those three elements come together it becomes a very powerful collective force.
On the night it proved to be too much for Wales, and it was epitomised by Chris Robshaw's 26 tackles, with no misses, and no penalties conceded either. Two years ago Robshaw led an England side into a Grand Slam game on the same ground, and saw it slip away. Those are the occasions when you hit rock bottom in sport, and you have to be resilient and learn and adapt.
Robshaw proved early on that he has done that. He took command even before the match began by telling the referee, Jerome Garces, that he would take his team out onto the pitch only if he ensured Wales followed within a minute and did not keep England waiting.
It was an important statement from a player whose captaincy and position have always been open to question, most recently with Steffon Armitage pressing his case. We have been crying out for an old-fashioned No.7, but what we know about Robshaw after 33 Tests is that he is a player who will stand up when the pressure is on.
Wales have lost only once at home in their last nine games in the Six Nations, and have lost at home to England only once on their last six visits to Cardiff. Also, given how emphatic their last victory was over England, this was a very significant result.
Another highlight was seeing Jonathan Joseph continue his form for Bath in his first Six Nations start. His try was beautifully crafted. Everyone at Bath knows about those quick feet, and there was a left-right-left movement in very little space that left Dan Biggar behind, before the dummy overhead pass allowed him to slip away from George North and Rhys Webb to score.
I've experienced that moment of exhilaration, too, and it's a great buzz. There were a couple of other good things from Joseph which highlighted his understanding with George Ford. On one occasion Ford's flat miss-pass saw Joseph find a gap and force a tackle from Jonathan Davies which left him at full stretch.
It showed how lethal his acceleration is, and this was a good first run-out for Joseph and the other two members of the Bath backline trio in Cardiff, Ford and Anthony Watson. I thought Watson took a difficult chance well, gathering a wicked bouncing grubber by Mike Brown very effectively.
England brought a lot of energy into this contest. They never sat back and, even when they went behind early on, their heads never dropped. They were disciplined, especially in the way they deployed their defence to deal with whatever Wales did. They were consistently good at shutting down space, and covered each other.
The only defensive lapse was for the Welsh try. Although it was questionable whether Taulupe Faletau's pickup from the scrum was legal, England did not defend the move well. After James Haskell was pushed off, Ford made the tackle on Faletau, but Jonny May showed a bit of inexperience by coming in when he didn't have to, and opened the door for Webb.
It's a Rugby League trait for wingers to come inside, and it may say something about the number of Rugby League coaches there are now in Union – but nevertheless May will be annoyed with himself.
England's defence is not a blitz, but they come very quickly for four or five yards and then assess the situation, either going up hard and straight or drifting wide.
One instance that typified the energy England had in defence was when Haskell made a tackle and Billy Vunipola stepped into the space behind the tackled player. This slowed down Welsh ball sufficiently for Robshaw to intercept Webb's pass.
I also had the impression that England's fitness has stepped up. Four years ago the Welsh were very effective at their round-the-corner game because they were so confident in their fitness. I'm not sure that is the case now. We've heard about Wales training hard through the Six Nations in order to be at peak fitness for the World Cup, but they looked flat and tired on Friday night where England looked fitter and fresher.
The only area of discipline that England must attend to is giving away unnecessary penalties. It is not a good move when the opposition have a kicker as accurate as Leigh Halfpenny to be conceding penalties in your own half on a regular basis. If the opposition are in the red zone, and you are in danger of conceding a try, then there is some excuse, but otherwise you should trust in your defence and remain patient.
Especially with England's improved fitness, because penalties give the opposition a breather. New Zealand work on keeping a high match tempo, backing their fitness against any other team. That's what England should be working towards.
Not that they should try to play the New Zealand way. They should stick to what they do best: scrum, lineout, maul and win the gainline. Quick ball and simple plays do nicely, with a little X-Factor from the speedsters.
Ireland away isn't going to be easy and although France at Twickenham should be a win, England can't be sure. The Cardiff win was massive; now England must back it up.
But if they maintain their discipline alongside their greater energy levels the results they crave will come.