The Heineken Cup 24th place play-off was a single game play-off that was formerly used to determine the final qualifier for the subsequent season's Heineken Cup.
This play-off was scrapped, effective with the 2009–10 season, due to changes in the Heineken Cup qualification format.
Through the 2009–10 edition, the Heineken Cup was open to clubs in the Celtic League, Guinness Premiership, Super 10 (now National Championship of Excellence) and the Top 14. The competition begins with six rounds of pool matches to determine the eight qualifiers for the knockout stages. 24 teams are arranged into six pools of four teams each, with the six pool winners and two best-placed runners-up entering the knockout stages. The 24 pool stage places were allocated as described below.
The first 22 places were awarded as follows:
The 23rd team was chosen from either France, England or Italy and was allocated to the country whose team progressed further in the previous season's Heineken Cup.
The European Challenge Cup winner received an automatic place in the Heineken Cup, taken from its country's allocation.
The final qualifier was determined from the result of the 24th place or Italo-Celtic play-off.
The final qualifier was the winner of the 24th place play-off, which took place between the best placed team in the Celtic League that did not automatically qualify and the best-placed semi-finalist in the Italian Super 10 competition. The play-off was a single match, which took place alternately in Italy or the home of the Celtic League side.
In 2007–08, this play-off was scheduled to take place before the Italian Super 10 semi-finals, so no Italian team was nominated to take part. This meant that the Celtic League nominee, the Newport Gwent Dragons, qualified without a playoff.
The play-off first came about in 2004 after the dissolution of the Celtic Warriors meaning that there would be only four Welsh teams to compete for four places in the Heineken Cup.
To ensure that there was some form of competition for the final place so not devaluing the league and provide an extra opportunity to increase the Italian representation in the competition, the final place in the Heineken Cup would be decided in a play-off to be played after the end of the domestic season.