Automatic entry to the 2019/20 Champions League group stage remains on offer to the winner.
Arsenal overturned an aggregate deficit against Rennes in the round of 16 and will have to get the better of Napoli in the quarter finals to keep progressing in the competition.
Chelsea, who made shorter work of the last 16 than their Premier League neighbours after thrashing Dynamo Kyiv 8-0 on aggregate, have now been paired with Slavia Prague, who shocked five-time winners Sevilla in the last 16 to reach this stage.
2018/19 UEFA Europa League Quarter Final Draw:
Napoli vs Arsenal
Villarreal vs Valencia
Benfica vs Eintracht Frankfurt
Slavia Prague vs Chelsea
First legs will be played on Thursday 11th April, with the return legs a week later on 18th April.
UEFA have also drawn the semi final pairings for later in the competition.
2018/19 UEFA Europa League Semi Final Draw:
Napoli/Arsenal vs Villarreal/Valencia
Benfica/Eintracht Frankfurt vs Slavia Prague/Chelsea
The winner of semi final two, contested by the winners of Benfica/Eintracht Frankfurt and Slavia Prague/Chelsea, will be the designated home team for the final, scheduled for Wednesday 29th May at the Olympic Stadium in Baku, Azerbaijan.