Liverpool manager Jurgen Klopp brushed off criticism of Andy Robertson, saying the left-back's performances were taken for granted.

The Scotland captain was questioned after giving away a penalty during Liverpool's 2-0 loss to Napoli in the Champions League on Tuesday.

Robertson has been a star performer for Liverpool and Klopp said the 25-year-old deserved more credit, dismissing the criticism.

"The criticism has nothing to do with the expectation. It is to do with the world out there. He has played well for weeks and months and then you take it for granted," Klopp told UK newspapers.

"If there is one game less than another, you start asking what has happened to Andy Robertson. Nothing, it's completely normal. The game before, he was maybe the best player on the pitch.

"The [Jose] Callejon situation, we all agree that it was not a penalty. Was it smart from Callejon? Yes, if you want to be smart like this.

"He wanted to get Robertson out of the game with little challenges here and discussions with the referee, and he got a harsh yellow card, but you face very experienced players and they try everything to decrease your quality.

"Nothing else happened. It was a completely normal game from Robbo."

Top of the Premier League by five points, Liverpool make the trip to Chelsea on Sunday looking to improve what has been a poor recent record away to fellow 'big six' sides.

Liverpool have won just one of their past 12 Premier League trips to 'big six' teams, a record that surprised Klopp.

"This is not good news obviously, but performance-wise, that's why it's so surprising. It is not an obvious problem," he said.

"We were often close to winning these games. [Over the past three years] it was pretty rare that it was a performance that deserved to lose an away game. So let's just keep going and we will see what happens."