They may be Racing Metro and British & Irish Lions team-mates, but Jamie Roberts plans on giving Johnny Sexton the silent treatment when Ireland meet Wales in the Six Nations on Saturday.

Ireland were crowned Grand Slam champions of Europe in Cardiff six years ago - and Wales star Roberts says he will never forget it.

Roberts opposes Ireland for an eighth time during his 68-cap Wales career on Saturday, with the stakes again high.

Defeat for Wales at the Millennium Stadium will end their title hopes, while an Ireland triumph would leave them needing victory over Scotland next week to secure a second successive Six Nations crown and complete their first tournament clean sweep since 2009.

Jamie Roberts and Johnny Sexton chat during Racing Metro training © Getty Images

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"When you always come up against the Irish, there is always kind of that edge to it," Wales centre Roberts said.

"We are good mates off the field, and certainly on the field down the years there have been some great games.

"Looking back on a personal note, though, there have been more lows than highs against them. That is something I am quite keen to rectify.

"I remember the quarter-final of the [2011] World Cup and 2012 [Six Nations] as very good memories, but I will never forget 2009 watching Ireland win the Grand Slam in our stadium.

"That is one of those moments in your career that drives you and motivates you I suppose. It's something you never want to happen again.

"And certainly the last two years, playing at home in 2013 we got blown off the field in the first-half, and last year it wasn't pretty, it was a poor loss out there [in Dublin]."

Wales' home defeat against England last month meant they could afford no further Six Nations slip-ups this season in pursuit of a possible fourth title during Warren Gatland's coaching reign.

And centre Roberts admits there is a huge sense of anticipation surrounding the latest meeting - effectively a win-or-bust scenario - between Wales and Ireland.

"It is one of those games that will stick long in the memory, whether it is a win or a loss," he added.

"It is one of those big games that do not come around too often in your career. It is against a team that is the best team in Europe at the moment.

"It is why we play the game, it's why we do what we do. You play the game to wear that jersey for Wales and play in the biggest games of all. This is a huge match.

"If we win, we stay in the hunt for the championship. If we lose, we are out of it.

"We play a formidable team who have a way of playing the game. Their attacking kicking game, their tactical kicking game - certainly from the half-backs - is very evident.

"They always come up with a trick play or two, so we have to be prepared for that.

"It is who blinks first, but it is also who dares wins as well. It is a bit of a game of chess these big games.

"We have to be ready to go out and play and take the game to them. They are very clever defensively, they pick and choose their rucks, and we have got to be very clever in that respect. It is certainly a thinking man's game this weekend."

If Ireland march to Murrayfield next week unbeaten, then fly-half Sexton will undoubtedly have had a major influence on matters at the Millennium Stadium.

"Johnny is the commander-in-chief of their team," Roberts said. "He is a clever player, a very, very good player and a guy we need to stay a few seconds ahead of on Saturday.

"We are good mates now in Paris, but he is a guy who demands high standards, and there is nothing wrong with that.

"He has got Ronan O'Gara as his mentor in Paris, who is passing on a lot of information to him and helping him develop into a wonderful player."

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