Liverpool's Joe Gomez takes the dizzy penalty challenge
Liverpool were in the title race up until Christmas but Jurgen Klopp's side fell away with a string of poor results against teams in the bottom half of the table, including Swansea and Hull.
The Reds are currently third with four games remaining and look set for a finish in the top four.
Merson thinks it will have been a successful season if they end up in the Champions League places but insists they must improve next year.
SKY SPORTS
Paul Merson says Liverpool must spend big in this summer's transfer window
He's a very likeable man, we all like listening to him and watching him. I think that's a big advantage, but it's who he buys
Paul Merson on Liverpool boss Jurgen Klopp
"Oh definitely. If they want to kick on, then yeah (they must spend big)," he said on Sky Sports.
"For me they've got to. The name of the game this season was to get in the Champions League.
"If they stay where they are, it's been a very good season.
SKY SPORTS
Paul Merson says Liverpool will have had a successful season if they finish in the top four
Invalid email
We use your sign-up to provide content in ways you've consented to and to improve our understanding of you. This may include adverts from us and 3rd parties based on our understanding. You can unsubscribe at any time. Read our Privacy Policy
"They have to go and buy players. I saw he (Klopp) was coming out saying that everyone wants to come to Liverpool, this is a good club, players will sign for us instead of going to London. He needs to do that.
"I think people will go there because of him.
"He's a very likeable man, we all like listening to him and watching him. I think that's a big advantage, but it's who he buys."
