Jurgen Klopp urged his side to be at the top of their game as they take on Red Bull Salzburg at Anfield on Wednesday night.
Liverpool lost 2-0 to Napoli on match-day one, succumbing to a late penalty from Dries Mertens and a Fernando Llorente goal in injury-time.
The Reds remain favourites against Salzburg, despite their impressive 6-2 victory over Genk in their Group E opener, although Klopp insists the Reds will have to work "really, really hard" at Anfield to edge them out.
“[Salzburg] will defend with all they have, they have waited so long for the Champions League,” he told reporters on Tuesday.
“I think they got kicked out nine or 10 times in the last qualifying round.
“They are the serial champions of Austria but then couldn't make it but were quite impressive in the last two years in the Europa League.
“So, it will be interesting and people should not be surprised if we have to work really, really hard. We need everybody, we really need everybody.”
Matip is expected to be back for this weekend's meeting against Leicester City at Anfield but the knock is serious enough for him to miss out against Salzburg.