Crystal Palace’s opening-day WSL victory over Everton is under investigation after the club made four substitution windows, with former referee Keith Hackett calling for the match to be replayed.

Crystal Palace's return to the Women's Super League was supposed to be remembered for all the right reasons.

A 1-0 victory over Everton, a clean sheet and a winning start to life back in the top flight gave Jo Potter's side the perfect opening weekend.

But just days later, the result is at the centre of a major controversy.

Palace used four separate substitution opportunities during the second half, one more than the three permitted under the Laws of the Game, with Kirsty Howat entering in the seventh minute of stoppage time.

The incident is now being investigated, with both the club and match officials under scrutiny.

And former Premier League referee Keith Hackett has gone further, suggesting the game should potentially be replayed.

Why Is Crystal Palace vs Everton Under Investigation?

Crystal Palace defeated Everton 1-0 on Sunday, with Lexi Lloyd-Smith scoring the only goal of the game in the 34th minute.

The controversy came late in the match.

Palace had already used their three permitted substitution opportunities when Howat was introduced in the 97th minute.

The WSL allows teams to use up to five substitutes, but those changes must normally be made across a maximum of three substitution windows, with half-time changes excluded from that limit.

Palace's first three substitution windows came in the second half before Howat's introduction created the fourth.

The official match report confirms Howat was brought on in the 90+7th minute, shortly before the final whistle.

That has left the league facing a difficult question: what should happen to the result?

Could Crystal Palace vs Everton Be Replayed?

The incident is particularly unusual because the breach appears to have gone unnoticed during the match.

The Laws of the Game are clear that, in competitions using five substitutes, teams have three substitution opportunities. Multiple substitutions made during the same stoppage count as one opportunity.

Palace's fourth window therefore created a breach of the competition's substitution rules.

The WSL has launched an investigation alongside the clubs and Pro Ref, while the match officials have been stood down from the following round of fixtures.

However, responsibility is not necessarily being placed solely on Palace.

The officials were also responsible for managing the substitutions and ensuring the rules were followed.

That is what makes the potential punishment so difficult.

Why Keith Hackett Believes Crystal Palace vs Everton Should Be Replayed

Hackett believes the situation is serious enough for the WSL to consider replaying the match.

Speaking to Goodison News, the former referee argued that both the team and officials could be considered at fault.

He questioned why the fourth official, who has access to the substitution information, did not prevent the additional substitution from taking place.

Most significantly, Hackett suggested that the WSL should consider whether the match needs to be replayed particularly because Palace ultimately won the game.

That would create an extraordinary situation for the league.

A result that appeared settled on the pitch could potentially be revisited because of an administrative error.

What Is the WSL Three-Window Substitution Rule?

The controversy also highlights a part of the modern game that supporters may not immediately be familiar with.

Teams can use up to five substitutes in top-level competitions, but they cannot simply make those five changes whenever they want.

Under Law 3, teams are restricted to three substitution opportunities during the match, with additional changes allowed at half-time.

For example, a team could replace two players during one stoppage and another player during a second stoppage. That would count as two opportunities rather than three.

Once the three opportunities have been used, further substitutions are not permitted unless a specific exception applies.

In Palace's case, the issue was not the number of players they replaced but the number of separate occasions on which they made substitutions.

What Could Happen to Crystal Palace vs Everton?

The WSL now has to decide what punishment, if any, is appropriate.

The possible consequences could range from a warning or financial sanction to a points deduction or replay, although the final outcome will depend on the investigation and relevant disciplinary process.

There is also the question of responsibility.

Palace may have breached the rules, but the officials also failed to prevent the substitution from taking place.

That could make this a much more complicated case than a straightforward punishment for a club.

And because the game finished 1-0, with Palace taking all three points, the decision could have a direct impact on the league table.

What Crystal Palace vs Everton Investigation Means for the WSL

For Crystal Palace, this was supposed to be the perfect start to their return to the WSL.

Instead, their first victory of the season is now surrounded by uncertainty.

For Everton, meanwhile, the possibility of another outcome could make the controversy even more significant.

The WSL rarely faces situations where a completed match could potentially be replayed because of a substitution error.

Whatever decision is eventually reached will therefore set an important precedent.

The question is no longer simply whether Crystal Palace broke a substitution rule.

It is how seriously the WSL believes that breach should be punished, and whether a mistake that happened during the game should ultimately change what happened after the final whistle.