'Fiery' Biggar ready for Ireland
Out-half's battle with Sexton will be central to Wales' hopes
It says a lot about how important Dan Biggar is to Wales' hopes of beating Ireland that the out-half has been rushed back from injury to play.
A shoulder problem was expected to rule Biggar out of the first three Six Nations games, but Warren Gatland is willing to take a chance on the man who makes Wales tick.
For many Welsh supporters, the 28-year-old was unlucky to miss out on making a Test appearance for the Lions last summer, but playing second fiddle to Owen Farrell and Johnny Sexton was always going to narrow his chances.
Gatland has already spoken this week about the need to stop the threat of Conor Murray and Sexton in Saturday's showdown at Lansdowne Road, and Joe Schmidt will be looking to do the same to Biggar and Gareth Davies.
Much like Sexton is Schmidt's lieutenant on the pitch, Biggar performs the same role for Gatland - whoever comes out on top in the battle of the out-halves will have a major say in which team emerges victorious.
Growing up in Wales, Rhys Ruddock played alongside Biggar at underage level and having spent the last few years in the same team as Sexton, the Leinster flanker is well aware of the threat that the Welsh No 10 poses.
"Underage he would have been the year above me, but I would have played with his year and he was always captain, so he's someone that I have a lot of experience playing with and have a lot of respect for," Ruddock says.
International Rugby Newsletter
"He's always someone that I would have looked up to, even at a young age he always had a huge work ethic and you could kinda see that he really wanted it.
"I think he's got all the attributes really. I just remember when we played together that a lot of it was to do with that mindset he had, he'd fight for everything.
"He wasn't afraid at all to put his body on the line, he would be playing 10 but he'd making as many tackles as a lot of back-rows back then, so he's got heart.
"He's a tough customer and hugely, hugely competitive. Not too dissimilar to Johnny Sexton in my mind. From playing with Johnny and Dan, they've just got that dogged sort of competitive nature about them.
"I definitely think he'll make a difference. I think it will probably be a difference in the way they play."
Having been handed the reins against England a fortnight ago, Rhys Patchell has gone from being the starting out-half to not even making Wales' match-day squad. Such is the ruthlessness at this level.
Wales, however, are a different beast when Biggar is pulling the strings and his selection, even if it is a risk, indicates that Gatland is expecting Ireland to kick the ball a lot.
The Ospreys man is solid under the high ball, as is Leigh Halfpenny, and the pair will be anticipating plenty of aerial bombardment.
Another Welsh out-half, Rhys Priestland, who misses the Six Nations with a hamstring injury, is in a good position to judge the out-half battle and, like his namesake, Ruddock, he can see plenty of similarities between Sexton and Biggar. "Johnny, in terms of his team management and what he demands from those around him, I don't think you will see many better than him on the field," the Bath player maintains. "If something is not right he will come up and tell you. He has that mentality to keep things in check.
"As a fly-half it is not so much what you can do but what you can do for the team and how you shape it and make the sum of the parts work better.
"And then Dan, he is a similar sort of character in that he demands the best from everyone else and he is quite fiery on the field and quite vocal.
"The thing that both of them have probably most in common is that they are ultimate competitors and that can be infectious for the rest of the team."
They may be similar players, but Sexton will be out to prove why he was ahead of Biggar for the Lions last summer.
Rhys Ruddock and Rhys Priestland were speaking at the launch of Rugby Players Ireland and Zurich's 'Tackle your feelings' app