#4 Ashley Young
Young has got a lot of stick lately for some his average performances, and his one-year contract extension didn't go down well with the fans either. Ashley is one of the few players in the side who has won a Premier League title and understands the magnitude of this kind of fixtures.
The 33-year-old has been restricted to defensive duties mostly in the big games this season, and it would be the same on Sunday as well. He would have a mammoth task of dealing with both Mane and Robertson down the left-hand side, and Young needs to use all his experience to thwart any attack from that flank.
#3 Luke Shaw
The revival of Luke Shaw at Manchester United is a story worth getting inspired by. After falling out of favor under Jose Mourinho and struggling with injuries, the England international held on to his ground and crawled his way back into the side.
Luke is now a regular first-team player at United after his impressive performances since the start of the current campaign. He marauds forward at will to link up play with Martial or Sanchez and performs his defensive duties diligently as well.
Shaw would have the responsibly to stop Mo Salah wreaking havoc near the United's penalty area and subsequently more forward to keep Trent Alexander-Arnold on his half as much as possible. The battle down that side could go a long way in deciding the outcome of this match.