The former Liverpool defender held no punches when trolling his fellow Sky Sports pundit in the aftermath of Man Utd's Friday defeat.

Friday saw Manchester United crash out of the FA Cup in disappointing fashion, losing to Middlesbrough on penalties after drawing 1-1 in normal time. While most of the post-match discussion surrounded the Boro's controversial equalizer, Jamie Carragher used yesterday's defeat to brutally troll fellow Sky Sports pundit Roy Keane.

The Red Devils played hosts to Chris Wilder's men in the 4th round of the prestigious cup, with Rangnick looking to build on their dramatic last-gasp win over West Ham in their last Premier League outing. Unfortunately, things were not meant to be for the 20-time English champions.

Jadon Sancho gave the home side the lead but the visitors drew level in the second half despite the ball hitting a Middlesbrough player's hand in the buldup. Man United squandered several opportunities to retake the lead only to enter a penalty shootout, which they lost.

After the game, Carragher took to Twitter to remind everyone of an infamous—and now viral—argument he had with Keane when the pair were on Sky Sports together. That heated topic of discussion surrounded Cristiano Ronaldo and whether the Portuguese ace was an unnecessary signing for Man United.

The iconic Irishman argued that while the five-time Ballon d'Or winner was not signed to win the club their first Premier League title since Sir Alex Ferguson's retirement, the Portuguese superstar was brought in to deliver silverware, namely the FA Cup. Ironically, the 37-year-old missed a crucial first-half penalty which might have secured them progression had he converted it.

"Roy Keane told me Man Utd had signed Ronaldo to win the FA Cup," the former Liverpool defender tweeted out.

With Man United out of both domestic cup competitions and the Premier League race, the UEFA Champions League stands as their only remaining shot at a trophy this season. However, Atletico Madrid stand in their way in the round of 16, meaning everything points to another trophyless campaign for the Red Devils.