Arsenal can make it a clean sweep for the Premier League in European competition tonight.
This season's Champions League final will be contested by Manchester City and Chelsea after they overcame Paris Saint-Germain and Real Madrid in their respective semi-finals this week.
And for the second time in three years, it could be an all-English final in both the Champions League and Europa League.
Manchester United already have one foot in the latter following a 6-2 first-leg win over AS Roma and Arsenal have it all to do in their second leg against Unai Emery's Villarreal in order to join them.
Trailing 2-1 from the first-leg, the Gunners have been handed a lifeline with Nicolas Pepe's penalty that could turn out to be crucial.
The good news for Arsenal in the Europa League semi-final tonight is that away goals do count.
A rule, which comes into effect in the result of a draw on aggregate after the second leg, first emerged in 1965 and was established in UEFA competitions towards the end of the decade - and has stood ever since.
That means one goal for Arsenal will be enough for them tonight if they keep a clean sheet against the La Liga side at the Emirates Stadium.
Furthermore, the away goal rule does count in both periods of extra time.
The only scoreline that would take the game into extra time and penalties is a '2-1' win for Arsenal.
But a '3-2' or a '4-3' win for the Gunners in 90 minutes or after extra time would put Villarreal in control of the tie by virtue of the away goals rule.
However, should Emery's side score once, Arsenal lose their away goal advantage and will therefore need to score three times to progress, making it 4-3 on aggregate.
