From Chelsea's relegation to £200m game - evolution of the play-offs

Middlesbrough beat Chelsea in the second ever Second Division play-off final to win promotion to the top tier and relegate the Blues [Getty Images] Chelsea have just finished 18th in the top flight, seven points clear of the drop zone. But after a two-legged play-off final against Middlesbrough, the Blues are relegated to the second tier. The year was 1988 and the play-offs were taking place for just the second time since being introduced the season before.

Boro had finished third in what was then the Second Division and won promotion by beating Chelsea 2-1 on aggregate. For those first two years of the play-offs, Division One teams would compete with Division Two clubs to decide who went up and who went down. It would be the last time that format was used.

And a lot has changed since then. What started out with games being played in front of 25,000 people at Ayresome Park has become the richest game in world football worth about £200m, contested with a 90,000-crowd watching on at Wembley Stadium. BBC Sport takes a look at the evolution of the play-offs.

Why were the play-offs created in the first place? Centre-back Peter Shirtliff scored twice in four minutes in extra-time for Charlton to give the Addicks a 2-1 replay win in the first ever play-off final in May 1987 [Getty Images] When the play-offs were introduced in the 1986-87 season, it was to facilitate a restructure of the leagues - including reducing the top tier from 22 to 20 clubs - in an attempt to improve the financial state of English football at the time. The plan was for the format to run for two years and be kept if they were considered a success.