Andy Robertson admits Liverpool's pressing has not been good enough this season.
The Reds suffered a stunning 4-1 loss at the hands of Napoli on Wednesday.
Asked about why it has been difficult for them to press this season, Robertson said: "We need to put our finger on it.
"We have to work out why that's happening. I can't put my finger on it just now because if we did it would have been sorted.
"But we have to get back to it. Our intensity over the years has been incredible, the way we work together, the way we press teams, the way we put them under pressure. And just now that's not happening, that's evident.
"It's not happening. The fans aren't daft, they can see it on the pitch as well. We need to do it quickly."