Liverpool's 2-1 victory at Newcastle on Sunday afternoon was as significant as it was dramatic. Despite being a goal and a man down inside half an hour, the Reds managed to defeat one of their main rivals for a top-four finish in this season's Premier League.
The way in which Newcastle wilted in the closing stages also illustrated that Jurgen Klopp's 'mentality monsters' remain capable of striking fear into the hearts of opponents. For all their problems over the past year, the players clearly still have the utmost faith in themselves to turn any game around.
The Reds unwavering self-belief is obviously rooted in the success they have enjoyed under their charismatic and doggedly determined manager - but perhaps also the fact that they now possess more depth up front than arguably any other team in Europe, as both Diogo Jota and Darwin Nunez so thrillingly illustrated after coming on as substitutes at St James' Park.
What Liverpool do not have, though, is anything like the same quality, variety and versatility in midfield or defence. Indeed, the game at Newcastle didn't just showcase the team's firepower - it also exposed their fragility.
Trent Alexander-Arnold was the unwitting star of another horror show at right-back, while Virgil van Dijk let himself and his team-mates down by getting himself sent off with a needlessly aggressive challenge on Alexander Isak just 28 minutes in, meaning the captain will now be suspended for Sunday's tricky clash with in-form Aston Villa.
Given there is no guarantee that Ibrahima Konate will have recovered from the muscular problem that ruled him out of the trip to Tyneside, Liverpool's need for a centre-back - preferably one that can serve as Van Dijk's understudy on the left-hand side of the defence - is painfully clear.
Furthermore, while Wataru Endo has made an encouraging start to his Anfield career, an improvement is required and it is impossible to shake the feeling that Klopp needs a long-term solution to his defensive midfield problem, the kind of 'project signing' that Romeo Lavia was meant to be.
As Jamie Carragher said on Sky Sports, "The squad that Liverpool have right now isn't good enough to challenge Manchester City, so they've got to go for it in the transfer market this week in terms of bringing in another defender and midfielder. That has to happen because Liverpool can still be the biggest rivals to Manchester City."
But at this late stage, with the window set to close on Friday, who could Liverpool actually sign? Below, GOAL runs through the best centre-backs and midfielders available, some of whom would cost far more than others...