Manchester City and Manchester United have both been given tough draws in the last 32 of the Europa League.
Premier League leaders City must tackle defending champions Porto, while cross-town rivals United have been paired with Ajax.
Should City progress, they will face either Legia Warsaw or Sporting Lisbon in the last 16, while United will meet either Lokomotiv Moscow or Athletic Bilbao if they see off Ajax.
Both Manchester clubs found themselves in the Europa League after being surprisingly eliminated in the pool stages of the Champions League.
City bowed out after finishing third in Group A, behind Bayern Munich and Napoli, while United were sensationally pipped to second place in Group C by Swiss minnows Basel.
Meanwhile, Stoke, the only other English side still in the Europa League, have been drawn against Valencia, who were denied a place in the knockout stages of the Champions League by Chelsea.
If Tony Pulis' side overcome their Spanish opponents, they will go on to face the winners of the tie between Trabzonspor and PSV Eindhoven.
Elsewhere, Italian outfit Lazio will take on Spain's Atletico Madrid in one of the ties of the last 32. Udinese, who finished second to Atletico in Group I, will square up to Greece's PAOK, who finished top of a pool which also featured Tottenham Hotspur.
Europa League Last 32
Porto v Manchester City
Ajax v Manchester United
Lokomotiv Moscow v Athletic Bilbao
Salzburg v Metalist
Stoke v Valencia
Rubin v Olympiacos
AZ v Anderlecht
Lazio v Atletico Madrid
Steaua v Twente
Viktoria Plzen v Schalke
Wisla v Standard Liege
Braga v Besiktas
Udinese v PAOK
Trabzonspor v PSV
Hannover v Club Brugge
Legia v Sporting Lisbon
First legs to be played on February 16, with second legs scheduled for February 23
Europa League Last 16
Salzburg/Metalistv v Rubin/Olympiacos
Legia/Sporting Lisbon v Porto/Manchester City
Steaua/Twente v Viktoria Plzen/Schalke
Wisla/Standard Liege v Hannover/Club Brugge
Stoke/Valencia v Trabzonspor/PSV
AZ/Anderlecht v Udinese/PAOK
Lazio/Atletico Madrid v Braga/Besiktas
Ajax/Manchester United v Lokomotiv Moscow/Athletic Bilbao
First legs to be played on March 8, with second legs scheduled for March 15