LIVERPOOL — Fortress Anfield has become even more impenetrable for visiting sides in the 13 months since Liverpool made Virgil van Dijk the world’s most expensive defender, but the commanding Dutchman’s absence for Bayern Munich’s visit in the Champions League leaves Jurgen Klopp with a selection headache.

Van Dijk is banned for the last 16, first leg on Tuesday after being booked three times as last season’s finalists squeezed through the group stages by the narrowest of margins thanks to more goals scored than Napoli.

In stark contrast to its Premier League form, where Liverpool has been beaten just once all season, Klopp’s men lost all three of their group games on the road against Napoli, Paris Saint-Germain and Red Star Belgrade to underline the importance of taking a lead to Germany for the second leg.

Three wins at Anfield pulled them through to the last 16 and Van Dijk has yet to taste defeat in 25 Premier and Champions League games on home soil as a Liverpool player, keeping 16 clean sheets in the process to tighten up a leaky defense that undermined Klopp’s first two years in charge.

“Straightaway he was organizing the defense, he was the leader at the back, and as time has gone on he is even more important,” said former Liverpool captain Sami Hyypia.

“He gives confidence to the players and makes many other players play better.

“It is very difficult to find a weakness. He is an ultimate centre-back.”

Missing the £75 million man is a big enough blow, but Liverpool will also be without Joe Gomez and most likely Dejan Lovren through injury.

Gomez underwent surgery on a lower leg fracture earlier this month, while Lovren has not featured since suffering a hamstring injury on January 7 and did not travel with the rest of the squad for a warm weather training camp in Marbella this week.

A makeshift center-back pairing of Joel Matip and Fabinho are therefore likely to be tasked with stopping another former pupil of Klopp’s — Robert Lewandowski.

The prolific Pole won two Bundesliga titles under Klopp when the pair were together at Borussia Dortmund and also lost the Champions League final against Bayern in 2013 before Lewandowski was lured to Bavaria a year later.

Bayern has been dominant in the Bundesliga since Klopp’s Dortmund won back-to-back titles in 2011 and 2012, but is playing catch up in the title race to Lucien Favre’s outfit this season.

“Of course over the years I have watched a lot of Bayern games and this season as well,” said Klopp.

“They were six times in a row champions of Germany, which is not easy, and they were one of the teams in the last 10 years who were pretty much all the time in the quarterfinals, semifinals, final of the Champions League.”

However, while Lewandowski, the in-form Kingsley Coman and the creativity of James Rodriguez and Leon Goretzka could post plenty problems for Liverpool’s undermanned defense, it is at the other end Bayern could also be exposed.

Ajax’s youngsters exposed Bayern’s weakness against pace in the Champions League group stages, while Bayer Leverkusen and Augsburg have also given Klopp extra encouragement in recent weeks in the Bundesliga.

As Van Dijk kept the back door shut, Mohamed Salah, Roberto Firmino and Sadio Mane fired Liverpool to the Champions League final last season.

Without their talismanic defender, all three will need to shine more than ever to give Klopp’s men a lead to defend when Van Dijk returns for the second leg on March 13.

Winger Franck Ribery and central defender Jerome Boateng also will not be available for the Germans’ Champions League campaign.

The pair were not included in the squad that left for England, with Ribery staying in Munich after becoming a father, and Boateng nursing a stomach virus. — Reuters