Manchester United earned a 3-2 win over Liverpool to book a place in the FA Cup fifth round.
Salah gave Liverpool the lead before Greenwood restored parity for Manchester United.
Marcus Rashford gave Manchester United the lead just after the restart.
Salah brought Liverpool back into the game with a deserved equalizer.
Bruno Fernandes came off the bench to score a superb free-kick as Manchester United earned a vital victory over Liverpool to progress in the competition.
Liverpool have lost back-to-back games in all competitions for the first time since March 2020.