Paul Merson says it would be 'unthinkable' if Liverpool missed out on a top-four finish as they prepare to face Chelsea in the Premier League on Thursday.
Liverpool ended a run of four defeats on the bounce on Sunday night with a 2-0 win over Sheffield United, but their extended difficult run has seen them slip to sixth in the table.
The Reds now sit two points outside the top four and could fall further down the standings if Everton and Aston Villa win their games in hand.
Meanwhile, Chelsea are yet to lose under new manager Thomas Tuchel, and while scoring goals has been challenging, their defensive record has improved markedly.
They drew 0-0 with Manchester United on Sunday afternoon and have earned 18 out of their last 21 points.
On Thursday, the two meet in what could be a vital clash in deciding the top four at the end of the season, and Merson admits that a loss would be disastrous for defending champions Liverpool.
"Liverpool and Chelsea and teams like that will be spending money on the strength of expecting that money to be coming in next season, Champions League money. That's why it's a big game - I don't think either team can afford to lose it," he told Sky Sports.
"I can't explain how big it would be if Liverpool ended up not getting in the top four, it's massive. Massive. Liverpool can't not be in the Champions League.
"People go over the years they might not have been in every year but this Liverpool team of the last two years have been, bar the last three months, unbelievable.
"To be out of the top four would be unthinkable. Unthinkable. They would've budgeted everything, everything about it - season tickets, everything.
"TV money from the Champions League, prize money for getting through the groups; it pays people's wages. They're not bottomless pits.
"They still have to look at their books. It won't be 'oh, don't worry about it'. And they need to bring in players. We've seen that with a few injuries they've become a lot less of a team.
"How are you going to get players to Liverpool now if they're not going to be in the Champions League? They need to get in the top four, 100 per cent."
Should the 'unthinkable' happen and Liverpool miss out on a top-four finish, they could still qualify for next season's Champions League by winning the European competition this year. The Reds were excellent in the first leg of their last 16 tie with RB Leipzig as they lead 2-0 on aggregate.
