The Boro manager beat the August transfer deadline by minutes in bringing the 24-year-old to Teesside as his seventh summer signing.

O'Neil goes into the Boro squad for Saturday's trip to West Ham with Southgate enthusing about a player he has been chasing for many months.

Southgate said: "Gary is a player that I have always had a strong interest in since I first got the job here. Despite his relative youth, he has played 200 games for Portsmouth and he has captained their team.

"He's very versatile and he's a good footballer. He is exactly the kind of professional I want at this club.

"He's in the right age bracket and he has the hunger that we are looking for. He is a ready made Premier League player."

There were reported fears over O'Neil's fitness following a summer ankle operation, though scans which took place at the time of his medical showed nothing more that routine scar tissue.

Southgate said: "We are absolutely delighted with Gary's high level of fitness.

"He is fit, and he is exactly the kind of player who I hope will be forming the basis of the team here for the next few years and help push us up the table to where we want to be.

"A lot of people keep saying that we needed to strengthen the right side and Gary has certainly played there a lot for Portsmouth.

"We have now got competition for places all over the field and I'm absolutely delighted about that.

"In fact I am very happy with the business that we have done over the summer.

"We have brought in a lot of young players in the right age bracket, and we will continue to give chances to even younger players, like David Wheater and Andrew Taylor, who are pushing through."

O'Neil revealed that he believes he can achieve a lot of his ambitions at Boro.

He said: "As soon as I knew that Middlesbrough were interested I was keen to come up here for talks. I was impressed at what they are trying to do here with a young squad. I can't wait to get started.

"It's a really good set-up. I can't see any reason why we can't challenge for a place in the top 10 this season."

O'Neil has been training on Teesside for a week now, and is getting his feet under the table.

He said: "The two weeks' break has been useful because it's given me the chance to get used to the lads. I have got involved in the team spirit and I have really enjoyed it.

"It's not easy moving when you have been at your previous club for such a long time. It can be a bit strange. But training has been good and everybody has made me very welcome.

"Obviously quite a few of the lads are away on international duty so I'll get to meet them all by the end of the week."

O'Neil admitted that he is happy playing in the middle or on the right hand side of midfield, though it's the right where he can expect to play most of his games for Boro.

With South American duo Julio Arca and Fabio Rochemback settling down in the centre of Southgate's midfield, O'Neil looks set to eventually oust skipper George Boateng from his current right-sided role - though there is no guarantee that the former Pompey man will be pitched straight into the starting line up at Upton Park.