Liverpool humiliated ten-man Manchester United 5-0 at Old Trafford in a stunning result in the Premier League. Goals from Naby Keita and Diogo Jota followed by a hat-trick from Mohamed Salah secured the Reds their biggest win over their Northwest derby rivals.The Red Devils found themselves 4-0 down in a shockingly poor opening stanza that also saw Cristiano Ronaldo escape a red card for kicking the ball onto Curtis Jones.However, more misery was in store for United after the break. Salah rounded off his treble just five minutes into the restart before United substitute Paul Pogba was sent off for a challenge on Naby Keita.Ronaldo appeared to had pulled a consolation goal back midway through the second half. But replays showed he was marginally offside.Everything that could have gone wrong for United, did, on the day. Meanwhile, the calls for beleaguered manager Ole Gunnar Solskjaer's sack have grown louder than ever.On that note, here are the five hits and flops from Manchester United and Liverpool in the 208th Northwest derby:Hit: Mohamed Salah (Liverpool)Mohamed Salah has been on a tear this season.Coming into the match on the back of a nine-game scoring streak, Mohamed Salah was the man Manchester United feared the most. Their worst fears came true, as the Egyptian was an absolute nightmare for United.Lethal, devastating and relentless, Salah netted thrice in the evening to floor United. In the process, he became the first visiting player in the Premier League to score a hat-trick at Old Trafford.Liverpool FC@LFCYou're looking at the first opposition player to ever score a @PremierLeague hat-trick at Old Trafford 🇪🇬👑👏 @MoSalah 👏11:16 AM · Oct 24, 2021394956948You're looking at the first opposition player to ever score a @PremierLeague hat-trick at Old Trafford 🇪🇬👑👏 @MoSalah 👏 https://t.co/nhbkNzCITASalah should be a genuine contender for the Ballon d'Or award this year. That's because there's no one better than him on current form as he continues to break records and power Liverpool's title charge.Flop: Cristiano Ronaldo (Manchester United)Ronaldo endured the worst outing of his second United spell thus far.Poor Ronaldo. He doesn't deserve to go through this. The returning hero was supposed to transform Manchester United into title prospects, but his second stint with the club is turning into a nightmare.It's no secret that his form has been patchy, but against Liverpool, the Portuguese ace was genuinely underwhelming. He tried to get on the end of crosses, but cut a frustrated figure in attack.ESPN FC@ESPNFCThis is tied for the heaviest defeat of Cristiano Ronaldo's career 😟The only other 5-goal loss was in El Clasico 11 years ago.11:10 AM · Oct 24, 20216240736This is tied for the heaviest defeat of Cristiano Ronaldo's career 😟The only other 5-goal loss was in El Clasico 11 years ago. https://t.co/RRDkmfSpO4The game could've been much worse, for Ronaldo, who was lucky to escape a red card for a petulant foul on Curtis Jones in the first half. To exacerbate things, he then saw a sublime goal ruled out late on for a marginal offside. It just wasn't his day.