LIVERPOOL, England -- Here are three points from a dramatic night at Anfield as Liverpool advanced to the last-16 at Napoli's expense.

1. Alisson, Salah send Liverpool through to last-16

Brazilian goalkeeper Alisson Becker produced a world-class save to deny Arkadiusz Milik in stoppage time and sent Liverpool into the Champions League round of 16 following a 1-0 win against Napoli at Anfield. Mohamed Salah's goal on 34 minutes looked to be enough to clinch the victory required by Jurgen Klopp's team, but Liverpool would have been out had Milik not been denied by Alisson's point-blank save three minutes into injury time.

Liverpool, last season's beaten finalists, went into the game knowing that a 1-0 win or a victory by two clear goals in the event of a Paris Saint-Germain victory against Red Star Belgrade would see them through Group C. But with PSG coasting to the win in Belgrade and securing top spot for Thomas Tuchel's team, Liverpool's qualification as runners-up came with the realisation that they could face the likes of Barcelona, Real Madrid, Bayern Munich or Borussia Dortmund in the next round.

Liverpool were prepared for a tense night at Anfield against a Napoli team currently in second place in Serie A. But aside from Virgil van Dijk escaping a red card for a 13th-minute challenge on Dries Mertens and late misses from Jose Callejon and Milik, it was ultimately comfortable for the home side.

Liverpool should have won by a more convincing margin but were unable to translate their dominance and take their chances: The hosts had 22 shots but only four on target, adding to a fraught atmosphere. It meant that they had to rely on Alisson to produce his heroics in the dying stages to ensure they made it into the knock-out stages.

Mohamed Salah's goal proved just enough as Liverpool advanced to the last-16 with a narrow win over Napoli. Matthew Ashton - AMA/Getty Images

2. Van Dijk's booking could hurt Liverpool

Beyond Salah's goal, the biggest moment Tuesday involved their influential defender. Van Dijk had a lucky escape when he received only a yellow card for a 13th-minute challenge on Mertens, which could have left the Napoli midfielder with a serious injury. Van Dijk won the ball, but his follow-through caught Mertens with his studs, just above the Belgian's ankle, and the Liverpool centre-half was swiftly booked by referee Damir Skomina.

A week after lambasting Burnley for their physical approach during Liverpool's 3-1 win at Turf Moor, Jurgen Klopp cannot now argue that Van Dijk's tackle was clean and fair if he wants to be seen as being consistent on his view of challenges during a game. Even though Van Dijk was fortunate not to be sent off, the yellow card could still return to haunt him and Liverpool, with the booking triggering a one-game suspension for the first leg of the round of 16 due to UEFA rules about accumulation.

Van Dijk has been a huge influence on Liverpool since his £75 million arrival from Southampton in January. He has eradicated the defensive uncertainty and become a crucial cog in the team, so how Liverpool cope without him could decide their Champions League fate. By finishing as runners-up in Group C, Liverpool could face the likes of Barcelona, Real Madrid or Bayern Munich in the next round, and such a task will be so much more difficult without their talisman in central defence.

3. Koulibaly is the real deal despite defeat

Kalidou Koulibaly could be at the centre of the biggest transfer in January, with Manchester United and Chelsea both eyeing the £90 million-rated Napoli centre-half, who was voted No. 9 centre-back in the FC 100. Both United and Chelsea have placed a commanding defender at the top of their wanted list, and Koulibaly showed at Anfield that he would be tailor-made for the Premier League if either club could persuade Napoli to sell the Senegal international.

At 27, Koulibaly is at the peak of his powers, possessing the experience and physical strength that mark him as a world-class centre-half. Against Liverpool, he gave a master class in the art of defending.

Yes, he was beaten by a moment of Salah brilliance for Liverpool's only goal, but it was the only time Koulibaly put a foot wrong. He produced crucial blocks to deny Salah and Roberto Firmino and showed great pace to dispossess both players when on the break.

In an era when defenders have to play out from the back, Koulibaly also displayed that key aspect of the job. But make no mistake, he is a defender first and foremost, and Napoli will do everything in their power to keep him in January.

Champions League elimination might make them vulnerable to a big bid, something the likes of Man United and Chelsea will be monitoring.