Eric Cantona says Manchester United play football like an old man having sex - it only leads to disappointment.
Ole Gunnar Solskjaer's team continue to struggle with inconsistency this season, as they sit eighth in the Premier League after 18 games.
United, who have not lifted a Premier League title since iconic manager Sir Alex Ferguson retired in 2013, are currently 24 points adrift of leaders Liverpool and seven points behind a place in the top four.
The Red Devils went on a six-game unbeaten run in all competitions, but Watford brought an end to that run on Sunday with a 2-0 win at Vicarage Road.
Solskjaer said this week that he wants his side to be as good as Jurgen Klopp's Liverpool and hopes to turn them into title challengers who play with an "attacking" and "dominant" style.
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But United legend Cantona, who spent five years at the club and won four Premier League titles under Ferguson, feels the Old Trafford outfit are far from the level required to excite fans and compete for silverware.
Instead, the former France star says there is nothing pretty about watching Solskjaer's team, using graphic imagery to get his point across.
"Manchester United occupies a special place in my heart," he said to Otro.
"But watching United play now, it's a bit like making love as an old man. You try as hard as you can, but at the end of the day, everyone is a bit disappointed."
He added: "When I say things, sorry, about making love as an old man, I'm not speaking about me. It was just a metaphor."
Although he finds the team underwhelming this season, he is confident they will be back among Europe's elite before long.
"They will be back because it's the biggest club in the world," he added.
United welcome Newcastle to Old Trafford on Boxing Day before they travel to Turf Moor to face Burnley in their last match of 2019.
They kick off 2020 with a trip to north London to take on Arsenal on New Year's Day.