The Reds began the weekend five points clear, but they have already seen that lead diminish once and know that only victory will do against a West Ham side in poor form.
When a team chasing the title comes to town the main focus is naturally on them, but the poor form of West Ham has certainly not escaped the attention of their fans.
Victory over Arsenal last month seemed like the perfect platform from which to build, but the Hammers have since lost three games in a row across all competitions, conceding nine goals in the process.
An ignominious FA Cup exit at the hands of League One basement club AFC Wimbledon was a particularly chastening result - even more so considering they conceded four goals - and the pain will have been made even greater when Wimbledon were drawn against West Ham's bitter rivals Millwall in the next round.
It is the back-to-back Premier League defeats - and only one win in five - which may prove most costly in the long run, though, with the Hammers losing away to Bournemouth and Wolverhampton Wanderers while conceding five goals without reply.
The Hammers failed to even register a shot on target in that 3-0 defeat at Molineux, and Manuel Pellegrini will be demanding a response to a performance he acknowledged was about as bad as it gets at this level.
West Ham will at least be glad to return to the London Stadium, where they have lost just one of their last six games across all competitions and could win three on the bounce for the first time since their move from Upton Park.
The most recent of those home games was that 1-0 win over Arsenal, and West Ham will need to summon an even bigger upset if they are to come away with anything from the league leaders on Monday night.
Pellegrini will still believe that Europe remains a possibility for his side, with only seven points separating them from seventh, but they are also only nine points clear of the relegation zone now so, by that virtue, they cannot afford to discount the possibility of being dragged down the table either.
Upcoming matches against Crystal Palace and Fulham may ease those concerns, but Pellegrini must first look to do his former club Man City a favour by getting one over on Liverpool.
Recent Premier League form: WLDWLL
Recent form (all competitions): DWWLLL
Liverpool were left with a curiously mixed feeling of having missed a glorious opportunity, yet still improved their position, when they failed to fully capitalise on a Manchester City slip-up in midweek.
The Reds had the chance to move into a seven-point lead at the top of the table having been granted an unexpected favour by old favourite Rafael Benitez at St James' Park, but they were held to a 1-1 draw at home to Leicester City 24 hours later.
On reflection, the fans and players will recognise that they did still manage to increase their lead during the midweek round of fixtures, but it was a small tiptoe forward rather than a big stride towards that elusive 19th league title.
It was also the first time that Liverpool had dropped points to a team from outside the top six all season, and that may well offer encouragement to the rest that Jurgen Klopp's side are not invincible.
In truth, the Reds deserved no more than a point from the game, and despite still being five points clear there will be an element of concern about the team's recent form.
Since the turn of the year Liverpool have lost to Manchester City and Wolves, scraped past Brighton & Hove Albion and Crystal Palace and then dropped points at home to Leicester - a far cry from their imperious form to end 2018.
Klopp will hope to have shaken off the January blues, though, and back-to-back wins over West Ham and then Bournemouth will do wonders to steady the ship ahead of a huge double-header against Bayern Munich and Manchester United later this month.
Any dip in form must be taken into context, though; this is still Liverpool's best-ever performance at this stage of a season and one of the best in English top-flight history, and they travel to the London Stadium having won five of their last six league away games.
Indeed, the Reds have only dropped points at Stamford Bridge, the Emirates Stadium and the Etihad Stadium this term, while they have kept six clean sheets on the road - already more than they managed throughout the whole of last term.
The pressure may well be cranked up a few levels by the time they kick off, though, with Spurs having already closed the gap to four points by beating Newcastle on Saturday and Man City having the chance to make it two when they host Arsenal on Sunday.
Recent Premier League form: WWLWWD
Recent form (all competitions): WLLWWD
West Ham have been boosted by the news that Marko Arnautovic's foot injury is not as serious as first feared, and the Austrian could be in contention to feature on Monday night.
The Hammers still have a lengthy list of casualties, though, and Samir Nasri will miss the game with a calf strain while Jack Wilshere, Manuel Lanzini, Fabian Balbuena, Winston Reid, Carlos Sanchez and Andriy Yarmolenko are all longer-term absentees.
West Ham possible starting lineup:
Fabianski; Zabaleta, Diop, Ogbonna, Masuaku; Snodgrass, Noble, Rice, Anderson; Antonio, Carroll
Liverpool possible starting lineup:
Alisson; Milner, Matip, Van Dijk, Robertson; Henderson, Wijnaldum; Shaqiri, Firmino, Mane; Salah
Head To Head
Liverpool have dominated this fixture in recent years, winning the last four in a row and scoring four times in each of those games.
Only twice in top-flight history has a team scored four or more goals in five consecutive matches against an opponent, and the most recent of those came in 1933.
We say: West Ham 1-3 Liverpool
Liverpool's defence does not look as sturdy right now as it once did, so West Ham should be able to cause them problems at the back. However, the Hammers are in poor form at the moment and Liverpool should have enough to still come away with all three points.
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