Rio Ferdinand believes Liverpool are "vulnerable" ahead of their top of the table clash with Manchester United.
Ole Gunnar Solskjaer's side head to Anfield as league leaders and can go six points clear of their rivals with a win.
The Reds have not lost a league game at their Merseyside home for over three years however.
Yet Jurgen Klopp's side have struggled for form recently, failing to win any of their three games over the festive period.
Virgil van Dijk and Joe Gomez remain absent through injury which offers United a greater chance of upsetting the odds.
And Ferdinand has called on his former side to grasp the opportunity this afternoon.
He said on Twitter : "There are big games and then there’s the Liverpool game....
" #LFC are vulnerable, Utd need to smell blood & go for the kill - these are the moments you dream of as a Utd player!
"Let’s hope the @ManUtd players do it!"
The former United player won at Anfield on several occasions during his time at the club.
He scored a winner between these two, albeit at Old Trafford, in a 1-0 win back in 2006.
And Ferdinand recalled how Sir Alex Ferguson used to cite Liverpool's lack of quality and urged Solskjaer to do the same today.
He said: "Fergie always used to say to us at Anfield 'this ain't like the old Liverpool teams that used to play here'.
"Just that mention of them lacking some quality would put a spring in your step.
"Ole (or someone in that changing room) must be shouting that this is a weakened team to the last couple of seasons".
United held Liverpool to a draw at Old Trafford last season before losing 2-0 at Anfield in January.
