Chelsea and Arsenal would face the prospect of an extraordinary end-of-season play-off to determine which club finished third in the Premier League if results on Sunday conspired to make them inseparable.

Chelsea sit third in the table, two points clear of Arsenal in fourth and with a better goal difference of one. They have also scored two more goals than their London rivals but there is a combination of results on the season's final day, when Chelsea play at home to Everton and Arsenal travel to Newcastle United, which would see them finish dead level.

In the event of a Chelsea draw, if Arsenal were to win by a single goal margin and score two more than Chelsea, they would be equal on points, goal difference and goals scored, which would call for a historic application of the Premier League's rule C14. Arsenal need victory at Newcastle to guarantee their Champions League qualification.

The rule is to be used if an issue, such as the league championship or relegation places, remains unresolved after the season. The difference between finishing third or fourth is one such issue, as the third-placed team advances directly into the Champions League group stage while the one in fourth must contest a play-off.

The rule reads: "If, at the end of the season, either the league champions or the clubs to be relegated or the question of qualification for other competitions cannot be determined because two or more clubs are equal on points, goal difference and goals scored, the clubs concerned shall play off one or more deciding league matches on neutral grounds, the format, timing and venue of which shall be determined by the Board."

The timing of a play-off would represent a headache for the Premier League. Chelsea have an end-of-season tour to the United States to play friendlies against Manchester City next week and then there are the England friendlies at home to the Republic of Ireland on 29 May and away in Brazil on 2 June. Neither Chelsea nor Arsenal would want the season to stretch into June. For Chelsea, the play-off would be the 70th game of their season.

There has never been an end-of-season play-off in the Premier League, although the organisers did have to prepare for the possibility of one towards the end of the 1995-96 season when Manchester United and Newcastle United were vying for the title. The title play-off would have taken place at Wembley on either 16 or 21 May and a first run of tickets was printed.