DAN Lydiate’s injury is a “massive” blow and Wales’ back row will have to defend like demons to make up for the absence of their tackle king.

That’s the view of the blindside flanker’s Newport Gwent Dragons teammate Toby Faletau.

The Rodney Parade region’s number eight is the sole Dragon in Wales’ 35-man squad for this autumn’s four home games which kick off on Saturday against Argentina.

Faletau, 21, is set to win his 18th cap against Los Pumas at Cardiff’s Millennium Stadium in a much reshuffled back row.

Form player Ryan Jones is also absent, a shoulder injury keeping him out this weekend although he hopes to be fit to face Samoa a week on Friday.

‘Chop tackle’ maestro Lydiate broke a bone just above his left ankle in the Dragons’ 32-12 league victory over Edinburgh in late September.

He was one of Wales’ key players in the 2012 Grand Slam triumph and is not expected back in action until the middle of the Six Nations, either late February or early March.

Lydiate’s prodigious tackle count for his country last season – clocked at 147 – was an instrumental factor in Wales’ impressive World Cup campaign and Six Nations glory.

Faletau said his is a hard act to follow: “Dan is a massive loss. He was the Six Nations’ player of the tournament last season and is a hard player to replace for the Dragons and Wales.

“Some of the things he does do not get noticed by everyone. We will all have to do more in defence.”

Faletau expects a tough time of it this autumn with Wales facing Argentina, Samoa, New Zealand and Australia over the next four weeks.

He thinks the tough South Americans will present a big first hurdle for Wales on Saturday after an encouraging campaign in the recent inaugural Rugby Championship.

Argentina narrowly failed to achieve their first victory over South Africa after being held 16-16 by the Springboks in Mendoza and led Australia by 13 points before losing 23-19 to the Wallabies on the Gold Coast.

“It’s a good line up of games this autumn with some big challenges ahead for us,” Faletau said. “I think Argentina surprised a few people in the Rugby Championship.

“They are physical boys and they were a bit unlucky against South Africa and Australia. Argentina are a good, physical side.”

Faletau is also looking forward to playing against one of the world’s finest number eights in opposite number Juan Martín Fernández Lobbe, the Toulon player also Argentina’s captain.

“I’ve never played against him before. He is a key player for them and playing well at the moment,” he said.