Ben Foster calls former Chelsea striker Diego Costa a 'filthy RAT' and Nemanja Vidic 'a sicko' as he names them as his worst opponent and biggest hardman in hilarious interview - but which ex-Man United team-mate is the worst trainer he's ever seen?
The 37-year-old, who spent five years at United between 2005 and 2010, has come up against some of the world's best players in his career, having primarily played in the top-flight.
Foster is currently plying his trade in the Championship with Watford but has opened up on his days in the Premier League, naming his least favourite opponent ever, the biggest hardman and the worst trainer he's come across.
When asked who he disliked playing against the most, Foster named an ex-Chelsea striker whose reputation for being an awkward opponent precedes him.
'It's a good question and it's Diego Costa because he was just a filthy little rat,' Foster told The Cycling GK YouTube channel.
'He would just snarl and scratch and he wouldn't leave you alone and he wouldn't give you a second's breath.
'And do you know what, Luis Suarez was a bit like that as well. He was horrible to play against, he would kick you, he would scratch, he would do anything.
'But just pure winners, I love those type of players. You want those types of players on your team. Animals!'
Another type of player Foster believes is fundamental to achieve success is a tough-tackling, no-nonsense figure.
Having been in the same dressing room with many throughout his career, who was the hardest?
'[I was with Roy Keane] only for a little bit and he did scare the life out of me, to be fair. He was a scary bloke,' Foster added.
'Nemanja Vidic was a bit of a sicko as well, to be fair. I'd say Nemanja. He would happily put his head on the end of someone's boot to stop a ball going in. Yeah, sicko.'
If that was a tougher question to answer, Foster was in no doubt as to who gets the nod for the worst trainer he's ever seen.
'Carlos Tevez, 100 per cent,' he said.
'He was a shambles in training, it did not interest him whatsoever.
'He didn't care, training wasn't even a thing for him. He was awful. But on a Saturday afternoon though, oh my gosh, what a player.
'Just that winning mentality, gave everything he had and was an unbelievable talent on the pitch on a Saturday afternoon.'