RHYS Webb has enjoyed a stunning rise on the Test scene but knows both he and Wales half-back partner Dan Biggar must be at the best to win the battle with Irish aces Conor Murray and Johnny Sexton.

The two best combinations in Europe go toe-to-toe in the crunch Six Nations encounter at the Millennium Stadium this afternoon.

If Ireland win then they will be a Murrayfield win away from a Grand Slam and they will look for Lions pair Murray and Sexton to pull the strings behind their abrasive pack.

The duo put the boot into England in Dublin a fortnight ago, giving Stuart Lancaster's men a torrid time with their smart and varied kicking game.

Webb hopes that his teammates don't give the Munster-Racing Metro combination as much time in their bid to win the aerial battle and find space.

"It was an outstanding kicking performance," said Webb. "I don't know if England did much analysis on them, they didn't seem to put much pressure on nine and 10 whatsoever.

"The kick is only as good as the chase, and playing with Tommy Bowe at the Ospreys , every time I put a box-kick up, he would always go and get it back for me.

"Murray and Sexton are key players, but Bowe, Rob Kearney and Simon Zebo are good in the air and their chase is obviously as good as the kick.

"They have got a lot of dangerous players. We just need to be on the money and we know there is no margin for error because Sexton will keep kicking the three points over and he can put us in the wrong parts of the field.

"We just need to keep on top of it and keep lots of pressure on them."

Webb has gone from strength to strength since being picked ahead of Mike Phillips for the opening autumn international against Australia in November.

The Ospreys man has scored four tries in his last six Tests and also made the break that enabled regional teammates Dan Lydiate and Biggar to combine for the crucial score against France in Paris.

Webb's progress means that teams are wise to his sniping but the scrum-half knows he needs to keep the opposition on their toes to enable his teammates to thrive.

"If I do see a gap, then I am going to go," said the 26-year-old, who was a ball boy at Bridgend when assistant coach Rob Howley was at the Brewery Field.

"If we score from it, or make yardage and get over the gain-line, then it is all going to help the team and get front-foot ball. Then hopefully speed of ball can create some space out wide for our dangerous backs.

"You just have to pick your moment, really. You can't do it all the time. It is about being smart and picking the right time to go."