Furious Hamish Watson insists Zander Fagerson should be absolved of blame for Scotland's sudden collapse against Wales as he hit out at referee Matthew Carley for sending the prop off.

Gregor Townsend's side looked on course to back up last week's historic win over England as tries from Darcy Graham and Stuart Hogg put them firmly in control at Murrayfield.

But Wayne Pivac's visitors were allowed to pinch a narrow 25-24 win as the Dark Blues crumbled.

Fagerson was dismissed 13 minutes into the second period after Carley decided the Glasgow forward had made contact with Wyn Jones' head as he cleared a ruck.

But an angry Watson mounted a staunch defence of his team-mate as he insisted it was not even a foul, never mind a red card offence.

And the frustrated Edinburgh flanker claimed it was the 20-minute period either side of half-time in which Wales ran in three tries which did the real damage to Scotland's chances.

Adamant Fagerson should hold his head high, Watson said: "Zander will be fine. That was a rubbish call. An absolutely dreadful call. That's not rugby, that call.

"Zander is absolutely fine. We've already got round him. He's a great player and a big part of everything we do with Scotland.  He can hold his head high, I think.

"We lost that game in the last 10 minutes of the first half and the first 10 of the second. We lost that game when we had 15 on the field. Z has nothing to worry about."

Former Wales and Lions captain Sam Warburton, co-commentating for the BBC, insisted the dismissal was harsh, with Jones moving upwards as Fagerson came in.

Television Match Official Karl Dickson appeared to agree as he seemed to suggest a yellow card would have sufficed. But Carley insisted a red was required as Fagerson became just the third Scot in Six Nations history to be sent off.

Watson continued: "I haven't heard the comms from the TV but I've heard from other people that the TMO said it wasn't a red, then the ref has overruled him. "The ref has the right to do that if he thinks that's the right call.

"We as players strongly disagree with that call. As soon as I saw it on the TV, I was thinking, 'That's not even a penalty'.

"There's not much else we can say. We don't think it's a red, a yellow or even a penalty. But that's the way the game is going."

Scotland conceded a mere six penalties as they recorded their first victory at Twickenham in 37 years in their championship opener.

But they almost doubled that tally against the Welsh and Watson admits they allowed the visitors too many opportunities to apply pressure.

"Our ill-discipline cost us the game," he said. "It's not good enough and we're all gutted. We know how good a team we are but the fans deserved a better performance.

"It's gutting. Wales didn't win it. We had that game in our hands and we chucked it away. It's pretty tough to take."

Having finally chalked up a win in London, Scotland now head to Paris in a fortnight looking to record their first win in the French capital since 1999.

"France away is going to be 10 times harder than the game on Saturday," said Watson. "We know we're good enough to go to France and beat them, though.

"We haven't done that for a while so we want to get that monkey off our backs. Saturday doesn't change how good a team we are. We lost from our own undoing.

"But we still believe we can go to France then win these next three games.

"Saturday was a slip-up of our own doing and we will go to France full of confidence because we know how good a team we are."