Jamie Roberts: Knocked out cold – but I can still recall how badly we played

I cannot remember leaving the pitch at the Millennium Stadium last weekend but I can't wait to get back on it tonight. There is a desperation across the team to get out there again and right the wrongs of the Argentina game – we owe the Welsh public a drastic improvement.

It's been a tough week. My memories of Argentina are hazy to say the least. It is the first time I have ever been knocked out cold on a rugby pitch. It was my fault – I didn't get my technique right in the tackle and Gonzalo Tiesi caught me on the sweet spot on my chin. I went out like a light – gone before I hit the ground.

I walked off the pitch but that is all lost in the haze. The first thing I remember is being in the medical room and watching the game on TV. I have watched the match back since and it did not make for good viewing.

We were well below the standard needed to win Test matches. Against a team of the quality and intensity of Argentina you are not going to win with that sort of performance. Credit where it is due to Argentina – they scored two good tries, limited our attacking game and they deserved everything they got from the match.

We are fortunate that rugby is one of those jobs where you get a chance to redeem yourself so quickly– so it is important for all of us who take the field in Cardiff tonight to make amends. That is what the fans and our coaches deserve. We have to be better.

Against Argentina at times we were tactically naïve. We played rugby in the wrong areas and should have looked to play more for territory – we lost the territory statistics by a margin. That's important to get right tonight. Secondly, our kick challenge was not good enough and against Samoa we cannot afford to be so lax again. But most costly was the simple fact that we switched off a couple of times and it cost us a couple of tries.

The preparation ahead of Argentina was good so it's understandable that the coaching team are so frustrated and disappointed. It comes down to us – the players are the only ones who can put it right. The responsibility is on us to correct the wrongs of last weekend; we have to deliver.

I'm fit and ready to go again and that is a relief. There are strict protocols to follow in returning to play after being knocked out. I did nothing on Sunday, some cardio work on Monday, got a bit more intense on Tuesday and then had contact on Wednesday before the medics gave me the all-clear.

Argentina was a fourth defeat in a row but the performances in Australia over the summer were not bad. Last weekend was a slide in performance and we know we are better than that – we still have a core of players who have fond memories of being successful in the Millennium Stadium, winning Grand Slams. Last weekend will be a motivation to get that feeling back for us, the coaches and our supporters.

We are expecting a bruiser of a game. Samoa are formidable opponents: athletic, physical and clever. Fifteen of their matchday 23 play in England or France. We beat them in the World Cup but it was one of the toughest matches I have played in my career. It was physical, very tough – you can't afford to miss tackles against these guys because they know how to punish you. And then when you have the ball it feels like you are running into brick walls against their tackling. We know what's coming.

They have improved noticeably over the past three years as they showed in the World Cup. The history books tell you that more often than not we beat teams like Samoa – but it was the same for Argentina and they beat us on our own turf.

I will be lining up alongside Ashley Beck for the first time tonight. He has the potential to be a very good player and now he has to take that regional form for the Ospreys onto the biggest stage. The scene is set for him – he has the attributes; he's big, he's agile, he's a good distributor, he's calm and cool on the ball, not afraid to take time on the ball.

Similarly, Justin Tipuric has been outstanding for the Ospreys and he faces the same challenge – can he reproduce it in a red jersey? Previously he missed out on selection because of Sam Warburton's class but this is his chance. This is what drives the squad forward, having quality of strength in depth – when you are looking over your shoulder knowing that if your levels drop there is someone who can compete for your shirt. That is how you get the best out of players at international level.