Jamie Redknapp fears Philippe Coutinho has lost his magic ahead of Liverpool's crunch clash with Manchester City next weekend.
In the absence of the injured Roberto Firmino, Liverpool laboured to a 2-1 win over Burnley on Super Sunday with Coutinho replaced by 17-year-old Ben Woodburn after an hour, shortly before Emre Can scored the winning goal.
Liverpool have won five of their last six league meetings with Manchester City, who they face live on Sky Sports 1 next Sunday, and the Brazilian has scored the winning goal in three of those matches.
Redknapp says Jurgen Klopp needs to spark Coutinho into life as Liverpool seek to seal a top-four spot in the final 10 matches of the season.
"The one worry for me is Philippe Coutinho at the moment," said the Sky Sports pundit.
"The man was on fire earlier in the season, he was the difference.
"But some of the magic has gone and he needs to try and get that back. That's the manager's job this week.
"Especially at Man City where he's had a lot of success in the last two or three seasons. That's a bit of a worry for me because he makes such a difference.
"When he plays well, so do Liverpool."
Liverpool have not lost against a side in the Premier League's top 10 this season and play rivals City and Everton in their next two fixtures, either side of the international break.
Fellow Sky Sports expert Jamie Carragher says Liverpool are likely to find those matches easier than they did against mid-table Burnley on Sunday.
"Certainly at Man City it will be more of a counter-attacking performance," he said.
"It will be a battle for possession, both teams like to have the ball, but when you think about what Liverpool did there with Coutinho, Adam Lallana and Firmino making penetrating runs in behind.
"City like to play a high line that plays right into Liverpool's hands. They've got Sadio Mane there as well now with added pace.
"Everton might be different. You'd expect Liverpool to have more of the ball at home and it will be a tough game, but for Man City Jurgen Klopp doesn't have to do any work this week.
"He can just show them the tapes of how they get on against the top five or six, who do play into Liverpool's hands and into their strengths."