I would put Yaya Toure in the top five of the toughest midfield opponents I faced in my career, and at his peak he could change games on his own.
Steven Gerrard probably edges it as the best I have played against, for his consistency over the years, but Yaya is up there along with Roy Keane, Patrick Vieira and Paul Scholes - which shows how highly I rate him.
Every midfielder has different attributes but the best players are the ones you fear, and I certainly did that when I was up against Yaya.
Even some of the very best play within themselves slightly, but he didn't. He would hurt you by going forward and by scoring goals at the end of it, which is always a great trait that not many midfield players have.
When I faced him, I knew he was very good on the ball and could pass it around me if he wanted to. He knew the moments to keep it simple and move the ball around.
But if you got too close to him to try to stop him doing that, he also had that ability to drive through midfield and his physical power and pace - which was deceptive because of his big stride - made it so difficult to stay with him.
Either by making a one-two or just by facing me up and running straight past me, he would be gone.
'He was bought to be a superstar - and he lived up to it'
Yaya is leaving Manchester City at the end of the season and I am glad he will get a proper send-off in Wednesday's game against Brighton, because he definitely deserves one.
In his eight years at the club since arriving for £24 million from Barcelona in 2010, he has played a huge part in City's rise, initially by being one of the first signings they made of a really top player from a big club.
Along with David Silva and Sergio Aguero, who followed him to Manchester, he was bought to be one of City's first superstars and he has lived up to that with the way he has performed down the years.
Yaya has played in so many positions but I preferred him as a deep-lying midfielder because he could do things there that others were not capable of.
He controlled possession and set the tempo for the team - then he unloaded and went forward to create or score. I loved that because it made him different, and made him very difficult to mark.
He has been a lot quieter this year but, in his first five or six seasons at Etihad Stadium, he was a big factor in the revolution of the club and signified the change that was happening there.
'You get defined by big goals - and Yaya scored plenty of them'
The big players score big goals in big games and Yaya has always done that for City.
Right from the start he has played a huge part in helping them win trophies, scoring the winner in the FA Cup semi-final against Manchester United in 2011, and doing the same against Stoke in that year's final.
He scored two hugely important goals against Newcastle as City closed in on the 2012 Premier League title and then there was the one he bent in against Sunderland in the 2014 League Cup final.
I found out for myself when I was at City for a year. The 2014-15 season was probably not Yaya's strongest campaign but I knew when he was in the team that he could pop up and make a difference in tight matches.
That is one of the differences between a good player, and a great one. Yaya produced when it mattered.
He was a regular goalscorer, a great penalty and free-kick taker, and a big character at the club.
'He had an aura - from the way he trained and the way he played'
As a team-mate, it was Yaya's presence that counted more than anything else in the dressing room.
I did not find him to be a big speaker - he was quite private and he is a family man off the pitch.
Some people might take it as a negative that he did not say much but I think it is just his personality. Some players are like that, and I don't mind it.
The way he was a big influence was the way he trained and the way he played. That gave him an aura.
'He has had to adapt to becoming a bit-part player, and he has taken it very well'
There has been another revolution at City since Pep Guardiola took charge in 2016 and Yaya has not been involved as much, especially this season.
I know myself as a player that, later on in your career, it is not easy when your role changes. He has had to adapt to becoming a bit-part player, which not every big player can handle, and I think he has taken it very well.
I would not have been sure that he would do that, because I never got that close to him personally. He was one of those players you did not quite know what he was thinking.
But like I say he was always quiet and got on with his job and I think it is to his credit that he has done the same even when he has been out of the team for so long.
Last season he was completely out of the picture at first under Pep, but got himself back in and earned himself another year's contract.
I think he deserves huge respect for that, because it is definitely not easy when you are in your mid 30s, and he also did it without complaining at all.
- BBC