Barcelona and Manchester United will meet in the Europa League play-offs for a place in the competition's last 16.
Spanish side Barcelona met the 2017 Europa League winners twice in the 2009 and 2011 Champions League finals, winning on both occasions, while United lost both legs of the 2018-19 European Cup quarter-final meeting between the pair.
"The draw has given us the most difficult rival again, like in the Champions League group stage. Luck was not on our side. Manchester United are a great rival, a historic club – the worst that we could wish for," Barca manager Xavi Hernandez said after the draw.
United finished second in their Europa League group this season behind another Spanish team — Real Sociedad – and meet a Barca side that missed out on the Champions League last 16 after finishing third in their group behind Bayern Munich and Inter Milan.
The eight group runners-up from the Europa League face eight third-placed sides from the Champions League group stages, with the winners of the two-legged play-offs progressing to the last 16.
The pick of the other ties sees six-time winners Sevilla facing Dutch side PSV Eindhoven, Serie A giants Juventus take on Ligue 1 team Nantes, while Jose Mourinho's AS Roma face RB Salzburg.
The first legs of the ties will take place on Feb 16, with the return match a week later on Feb 23.
Draw in full: Barcelona v Manchester United Juventus v Nantes Sporting Lisbon v Midtjylland Shakhtar Donetsk v Stade Rennais Ajax Amsterdam v Union Berlin Bayer Leverkusen v AS Monaco Sevilla v PSV Eindhoven Salzburg v AS Roma.