Manchester United and Liverpool end up playing at least two times in a football season (Premier League) and any other fixture between the two is a bonus. But as unbelievable as it sounds, the two teams have never met in European competition in their storied 122-year-old rivalry. Tonight, that record will be broken as they face off in the Europa League. Here's everything you need to know before watching this historic fixture: - After 194 encounters in domestic competitions, dating back to 1894, the fierce foes from England's northwest are crossing swords on the continental stage for the first time. - Both Liverpool and United would rather be in the Champions League -- they have been European champions five and three times respectively -- but with neither team assured of a top-four finish in the Premier League, they may need to win the Europa League in order to reclaim a place among the continental elite. - Liverpool v Man Utd is the first England v England clash in the UEFA Cup/Europa League since Liverpool v Spurs in April 1973. - Manchester United's away record in European competition is wretched: they havenâ€™t won any of their last five away knockout games, losing four times (D1). - Liverpool have reached the last 16 of a European competition for the first time since the 2010/11 season. - The dangerman for them though will be Juan Mata - who has been involved in eight goals in his last eight games against Liverpool in all competitions (three goals and five assists). - Current Man United manager Louis van Gaal has won all four of his previous encounters with Liverpool, including home and away wins in the league this season, and his side appeared to have turned a corner recently, winning four games in a row. - Liverpool are three points below United with a game in hand after coming from behind to win 2-1 at Crystal Palace, having previously claimed a measure of revenge for their penalty shootout loss to Manchester City in the League Cup final with a rousing 3-0 win over Manuel Pellegrini's men in the EPL. - The Europa League represents Jurgen Klopp's last chance to end his first season as Liverpool manager with a trophy in his hands. - United winger Jesse Lingard will miss the game through suspension after being booked in both legs of the 6-3 aggregate win over Danish side FC Midtjylland in the previous round. - Wayne Rooney's continued absence with a knee injury means that 18-year-old striker Marcus Rashford, who shot to prominence with a debut brace against Midtjylland in last month's 5-1 second-leg win, stands to get his first taste of the Anfield atmosphere. - Antonio Valencia could make his return following a foot injury, but Ashley Young, Luke Shaw, Bastian Schweinsteiger and Phil Jones remain absent, while Adnan Januzaj is cup-tied and Timothy Fosu-Mensah ineligible. - Liverpool playmaker Philippe Coutinho and striker Daniel Sturridge are expected to return to Liverpool's starting XI. - Nathaniel Clyne will take over at right-back from Jon Flanagan, who was not included in Liverpool's Europa League squad, but midfielder James Milner is doubtful after being sent home from training due to illness.