Arsenal and Chelsea both secured top spots in their respective Europa League groups long before Matchday 6.
And following the completion of group fixtures on Thursday, they now know the identities of the teams joining them in the last 32.
A heavily rotated Chelsea team drew 2-2 with MOL Vidi in Thursday's early kick-off, while the Gunners continued their unbeaten run with a 1-0 win over Qarabag.
The knockout stages of the Europa League will see third-placed teams from the Champions League drop down into the competition, leaving some potentially very tricky ties.
Who can Chelsea and Arsenal face? Potential last 32 opponents include: Viktoria Plzen, Club Brugge, Shakhtar Donetsk, Galatasaray, Zurich, Celtic, Slavia Prague, Fenerbahce, Olympiakos, Rapid Vienna, Lazio, Malmo, Krasnodar, Rennes, Sporting Lisbon/BATE Borisov.
There are 15 teams that both sides can potentially face comprising of both runners-up from other groups and the four unseeded teams who dropped down from the Champions League.
They cannot be drawn against the runner-up from their own group (Sporting for Arsenal, BATE Borisov for Chelsea) or a team from the same country.
The draw for the knockout stages of the Europa League takes place on Monday December 17 in Nyon, Switzerland.