Olympiakos 2 Manchester United 0: 'Flat, abject, hopeless' - Roy Keane, Gary Lineker and the football world react to shock Champions League defeat

Former captain had labelled the performance in the loss 'flat'

Roy Keane was critical of Carrick and his United team-mates (GETTY IMAGES)

Never one to mince his words, Roy Keane's launched a scathing attack on his former team Manchester United after their woeful display in the 2-0 Champions League defeat against Olympiakos - labelling it "flat", just like United midfielder Michael Carrick's post-match interview.

Fellow former footballers Gary Lineker and Dietmar Hamman have agreed that it was a pathetic performance in Greece, Manchester United's first loss in the country, while Queens Park Rangers midfielder Joey Barton has warned that the "dynasty [Sir Alex] Ferguson built will be gone in 18 months".

Gary Lineker, scorer of 48 goals for England between 1984 and 1992, wrote on Twitter: "MUFC have had the odd bad day over the years, but I cannot recall such an abject, hopeless, forlorn performance. And against such mediocrity."

Former Liverpool midfielder Dietmar Hamman, winner of the Champions League with the Reds in 2005, added: "Never seen Man United so helpless. Poor with and without the ball. Desperate times, desperate measures. Not many teams spent £70m net this season. I'm not sure whether the board will let the current manager spend the money in the summer."

Joey Barton, meanwhile, has sympathy for the struggling manager David Moyes. "Can't help but feel sorry for Moyes. Fergie left a squad in need of a major overhaul. If he left when he should have (5yrs ago)...If the Glazers and Woodwood don't produce 5 top quality signings, the dynasty Fergie built will be gone in 18 months. #mental"

Speaking on ITV, Keane reacted sharply to a post-match interview from Carrick, who succeeded him in the United midfield in the mid-2000s, in which his demeanour appeared jolted by what he had experienced.

"That interview was just like the performance: flat. He should say a bit more, have a bit more urgency even in his interview," Keane said.

"That just reflected United's performance tonight: flat, with no urgency.

"They keep saying, 'Ah, well, next game, next game'. For some of them there won't be another game for them. That's the reality."

Read more: 'United can still turn tie around,' claims Carrick
Comment: Excuses running out for Moyes after grim defeat
Match report
That's the worst United have played in Europe - Moyes