Anyone wondering why England turned to Joe Worsley this week should have a look at the tape of Wales versus Scotland last month. Not the final four minutes with its 10 points; we've all seen that often enough to commit every run, tackle, pass and kick to memory. No, look at the first 50 and remember the killer stat – that in all that time Scotland made only two mistakes.

Two mistakes in 50 minutes of rugby is, by definition, close on perfection. It just does not happen. Not even on the training ground, let alone in a Test match arena where everything is 100mph. It's like applying the principles of Swiss watch-making to the demolition business.

Anyway, after 50 minutes at the Millennium Stadium, Scotland looked to be running away with the game and largely because their back row was causing mayhem. John Barclay, Johnnie Beattie and Kelly Brown, ball carriers all of them, were running through tackles, bursting the defence wide open.

They are a well-matched trio – Barclay at 6ft 3in and a shade over 16st is the shortest and lightest, Brown at 6ft 4in and more than 17st is the biggest – and they know each other's game, all three playing for Glasgow where they are known as the Killer Bs. Take a back step and they can take a game away from you. So welcome, Joe Worsley, one of the game's great defenders.

He's no slouch when it comes to making the hard yards himself but Joe is one of those guys who can be relied on to do a job. Most will remember his performance against Jamie Roberts in last season's Six Nations but Worsley has proved time and again that defence and dynamic tackling do win games, tournaments even.

In 2007, when Wasps last won the Heineken Cup, there were some hairy moments even getting out of the pool stage – particularly at Castres, currently top of the French league, but then a pretty unfashionable club who tended to blow hot and cold about Europe. In the final pool game down there, which we needed to win, they were having one of their hot days. Luckily for us, so was Worsley.

We hung on to win by three points, 16-13, largely because he cut down anything that ran at us and did it on or behind the advantage line – his job at Murrayfield tomorrow in one of those games where tradition has it that form goes out of the window.

After playing so well in Cardiff, Scotland will be smarting at losing in Rome and England have never found Edinburgh an easy place to visit. I'm not going to list the upsets but I'm told that north of the border great play is being made this week that it is the 20th anniversary of the deciding game when Scotland took the grand slam from under the noses of England, playing the underdog card to perfection.

It's something they obviously enjoy and are comfortable with. For example, last autumn against a fancied Australia side, Scotland proved that cussedness and commitment can win games. Unfortunately, the other Scotland played Argentina a week later. They had tons of ball but lost a game they should have won.

However, you can bet your life that the underdog card is being waved again this week and that there will be no shortage of passion. It will be England's job to keep a lid on that passion and not get lured into playing a game that is foreign to them – something they did against Ireland.

To be honest, I have some sympathy with England. Stung by criticism of the dull way they played in Rome and having seen a corker of a game between Wales and France the previous night, the blood was up. Unfortunately, it turned out to be the wrong time and the wrong place.

England, who might have expected a little more sympathy from the referee Mark Lawrence, went off like a rocket. Determined to play, they went wide from the start, just as the heavens began to open. A cool head would have called a halt, pointed to the Irish corners and said: "That is where we play." Instead England forced the issue, got turned over and were playing catch-up rugby for most of the game.

Actually, they did it well enough and, had Lawrence been more southern than rigidly northern hemisphere in his approach, would probably have held on to that late lead. Instead they learned a lesson about thinking on their feet.