Jurgen Klopp says it is "absolutely insane" his side finished their Champions League group with 15 points after making it five wins on the spin with victory over Napoli.

The Reds were beaten 4-1 by the Serie A leaders in the reverse fixture on matchday one – a loss Klopp described as the worst performance of his seven-year tenure.

Liverpool recovered with wins home and away against Ajax and Rangers to qualify for the last 16 with a game, against Napoli at Anfield on Tuesday, to spare.

A 2-0 win saw Liverpool inflict some revenge on Napoli for their September mauling, but they fell two goals short of overtaking their opponents at the Group A summit.

Klopp's side will therefore be unseeded in Monday's last-16 draw, but the German was pleased with what he saw against Napoli, who entered the game unbeaten in 17 matches.

"We showed tonight a really good reaction," he told BT Sport, referencing Saturday's 2-1 loss to Leeds United that leaves Liverpool ninth in the Premier League.

"I would have enjoyed the game even without the goals. Being compact makes all the difference. All of a sudden we are difficult to play against.

"If you see what Napoli can do in the moment, it was a really good game in our situation. The boys played a good game with a lot of courage.

"I saw the bravery to go in for challenges, making a proper fight of it and two set-pieces give us the three points – 15 points in the Champions League group is absolutely insane."

The win over Napoli was Klopp's 400th game in charge of Liverpool, and his 100th in the Champions League with the Reds and Borussia Dortmund.

He is just the seventh manager to reach that milestone in the competition, while only Pep Guardiola (61) has won more than the German's 58 games in those first 100 outings.

Liverpool survived a scare when Leo Ostigard had a goal ruled out by a VAR check lasting more than three minutes, with the technology coming to the Reds' aid two more times.

Mohamed Salah gave the hosts the lead in the 85th minute and substitute Darwin Nunez, who played a part in that opener, added a second in the 98th minute.

Those two goals were also subjected to VAR checks, but Klopp joked he could have no complaints over the delays due to his side being on the right end of the decisions.

"I heard it was some technical issues [for the delay on the first goal]," he said. "It is tough but in the end it is good for us. 

"Three times in our direction. I did not see the first goal. But after a long time they seem to have made the right call."

Despite their 13-game winning run coming to an end in their first defeat since April, Napoli finished top of their Champions League group for only the second time (also 2016-17).

The Italian side had scored a competition-high 20 goals across their opening five group matches, but they mustered just two attempts on target at Anfield.

"We're very disappointed," said defender Ostigard. "We thought we were in the game, especially in the second half. To lose at the end is tough to take. We came here to win."