Ever since Vincent Kompany signed for Manchester City from German side Hamburg in 2008, the big defender has transformed into the best centre-back in world football.
The City captain has won two league titles, one FA Cup, one League Cup and one Community Shield with the club since arriving six years ago.
In that time, the 28-year-old has earned the respect and applause of rival fans and football critics due to his consistent displays at the back.
A strong yet pacey central defender, Kompany is known for his decision making and putting his body on the line for his club, making him a favourite amongst fans of not only Manchester City, but the Premier League in general.
So once Kompany departs Manchester City, who will be the Premier League's best defender?
In January this year, City's rivals Chelsea completed the signing of French teenage defender Kurt Zouma for £12 million from French club Saint Etienne.
The 19-year-old earned a reputation as one of the hottest prospects in European football in France with ex-Chelsea star Florent Malouda predicting him to become one of the greatest French players of all time.
When City signed Kompany, he was a young defender with huge potential, just like Zouma (who is three years younger than Kompany was when he came to the Premier League).
Despite Chelsea having the best defence by far in the league last season, Jose Mourinho's side have looked shaky at the back so far this campaign and a change could be needed.
Time for a change?
John Terry is a definite in the Chelsea defence but if Gary Cahill's early season form doesn't improve in the upcoming weeks, Mourinho could turn to Zouma to partner Terry at the heart of the defence.
On his Chelsea debut on Wednesday, he put in a solid performance against Bolton and even popped up with a goal, giving Chelsea fans an early sign of a player they might one day look at as one of the best in the business.
However, Cahill is likely to find form again so it is unlikely Zouma will become first choice for Chelsea this season but once Terry hangs up his boots in a couple of years, the Blues are going to need a replacement and Zouma is an obvious choice for the next decade.
If he does reach his potential, Zouma is likely to become the world's best defender, just like Kompany is today.