Former Ireland captain Rory Best says "ruthless" new IRFU performance director David Humphreys is "a brilliant appointment".

Humphreys has served as Ulster's director of rugby and spent six years in a similar position at Gloucester.

"He understands what needs to be done to win and he'll do that," said Best.

"Being brutally honest about it, David is ruthless."

Humphreys won 72 Ireland caps and captained Ulster to their sole European Cup success in 1999.

He is currently director of performance operations with the England and Wales Cricket Board and will join the IRFU in March, where he will work with Nucifora in a transitional period before taking sole charge on 1 June.

Since Nucifora was appointed in 2014, Ireland have won three men's Six Nations titles, one women's title while both men's and women's Sevens teams qualified for the Paris Olympics.

Best, who played alongside Humphreys at Ulster and was captain when he was director of rugby at Kingspan Stadium, believes "it is a strong appointment" by the IRFU.

"David has been a fantastic player and servant to Irish rugby, and when he retired and went into Ulster's director of operations role, he transformed Ulster rugby," Best told BBC Sport NI.

"David Nucifora has done a fantastic job. When you look at his record since he took over - it's been brilliant.

"Irish rugby is in a really, really good place. I think David has a different skillset in many ways and will be able to take it another step forward."

'Hard to win an argument with Humph'

Best says that while Australian Nucifora did a superb job as performance director, he "isn't everyone's cup of tea". The former Ulster hooker adds that Humphreys is a different character but will not be afraid to stamp his mark on the organisation.

"Along the way, it will not be going from Nuci, who upset everyone at times, to David, who will keep everyone happy," says Best, who believes his former team-mate will focus on balancing the provincial game and ensuring there is consistent depth at international level.

"He will do what he feels is right. If you're on board with that, great. If you're not, at points it won't matter as David will do what is right for Irish rugby.

"He'll want everyone to benefit, but be under no illusions, David will do what he feels is right. I crossed him a few times as a captain and it's not a particularly good place to be.

"He is a fantastic orator and he knows what he wants. It's a difficult place to be when you are trying to win an argument with Humph.

"He understands rugby union probably better than anyone I know. It's very important in that role, I feel, to have a strong grasp of rugby because you are trying to move structures and systems to produce better players.

"He also understands the business aspect of it. That will be important to David."