TAULUPE Faletau has been backed to rise to the challenge of tussling Lions rival and Ireland talisman Jamie Heaslip in Wales' crunch Six Nations encounter.

There will be fascinating match-ups all over the pitch at the Millennium Stadium on Saturday afternoon and none are bigger than the battle between the number eights.

The Grand Slam-chasing Irish have been boosted by the return of Heaslip, who missed their win against England after fracturing three vertebrae in his back against the French.

That sets up another mouthwatering head-to-head with Faletau, who was famously his rival for the starting jersey on the Lions' tour to Australia in 2013.

The Newport Gwent Dragons man got the nod for the third Test decider, a controversial decision that even grabbed the attention of the Manic Street Preachers' Nicky Wire, who backed the Welshman: "Toby Faletau or Jamie Heaslip? It's a no brainer!"

It's currently two wins apiece in the duel and fellow Lion Dan Lydiate predicts a huge contest in Cardiff.

"They are both quality number eights," said the blindside flanker. "Different players but both do their jobs very effectively.

"They are both really good ball carriers and Toby is maybe more explosive while Jamie finds the gaps and seems to break tackles.

"Even though Toby is laid-back he is a different animal when he gets on the pitch and that's why he is at the top of his game. He takes his rugby very seriously and relishes the challenge whoever he comes up against."

Heaslip, who comes in for Jordi Murphy, forms an imposing Irish back row alongside flankers Peter O'Mahoney and Sean O'Brien.

The Welsh triumvirate of Lydiate-Faletau-Sam Warburton is a tried and tested one and the six says they must be at their best.

"They have a very strong back row and Jamie coming back into the team only strengthens that. We're looking forward to the challenge," he said.

"Heaslip is a leader on the field, a really ball carrier and a nuisance at the breakdown and O'Brien and O'Mahoney make for a really strong unit and we're going to have to be on our best form to try and get the better of them."

O'Brien, nicknamed 'The Tullow Tank', is sure to put Lydiate's famed defensive skills to the test.

"He's not easy to stop," admitted Lydiate. "You don't want him to have big run-ups at you. It's about slowing him down before he gets going."