Mohamed Salah signs off with double in Liverpool’s frantic win over Newcastle

He was never leaving quietly. Mohamed Salah signed off for the Africa Cup of Nations with two goals and an assist as Liverpool eased three points clear at the Premier League summit against a deflated Newcastle. Jürgen Klopp is already counting the days until he returns. Salah’s final Liverpool appearance before representing Egypt in Ivory Coast was a test of the leaders’ composure and resources at the end of a demanding festive schedule. They passed convincingly on both counts.

Victory was ultimately comfortable against a Newcastle team that unravelled defensively as the game wore on, and would have been far more comprehensive but for a Salah penalty miss and fine goalkeeping from Martin Dubravka. But it was also a fierce examination of Liverpool at times.

Related: Jürgen Klopp thrilled by Salah’s impact … and recovery of lost wedding ring

Klopp’s team needed to find a way through Eddie Howe’s deep and compact visitors. They had to hold their nerve when chances went begging and Alexander Isak equalised from a rare Newcastle attack. “How we all took those missed chances was exceptional,” said the Liverpool manager. “Everyone was on fire. It was: ‘We go again, and again, and again …’ and we did.”

Not for the first time this season Liverpool’s leading marksman and their options off the bench made the difference. Salah’s brace took him to 151 league goals in a Liverpool shirt, only the fifth player in the club’s history to reach the 150 mark. Their xG of 7.27 was the highest ever recorded in a Premier League fixture too. Liverpool will consider the six-point swing in their favour over Arsenal in the past week of greater significance.

For Newcastle, however, a seventh defeat in eight matches, a striking lack of confidence in possession and some desperate defending – Dubravka excluded – increased the malaise. Howe argued that Liverpool’s fourth, a Salah penalty, should never have been awarded after substitute Diogo Jota tumbled after a slight touch from the Newcastle keeper. But he could not bemoan the outcome. “Naturally we are not at our most confident and we have to do everything to protect that,” he said. “But we can’t over-react or dramatise things.”

Liverpool started at a furious pace, their players and crowd alike sensing an inviting chance to stretch their lead at the top of the table. Trent Alexander-Arnold had a powerful drive deflected just wide after 90 seconds. The Newcastle goalkeeper produced a fine save to flick away a Darwin Núñez effort after he, Salah and Alexander-Arnold combined to carve open the visiting defence for the first time. The rebound fell to the excellent Curtis Jones but Fabian Schär blocked in front of his goalline.

Luis Díaz had a goal disallowed for offside against Núñez. Newcastle’s reprieve should have lasted seconds. Liverpool immediately regained possession and Díaz danced his way past Dan Burn inside the area before tumbling over Sven Botman’s challenge. The referee, Anthony Taylor, immediately pointed to the spot, VAR eventually concurred, but Salah drove the spot-kick straight down the middle and Dubravka pushed clear. Alexander-Arnold was first to the loose ball and sliced high into the Kop. Salah opted to change his boots during the interval.

Dubravka enjoyed a fine first half. The stand-in keeper foiled Núñez yet again when Botman slipped chasing a long ball and the Uruguay international was left one-on-one with Dubravka, who also saved the striker’s follow-up attempt. Alexander-Arnold did beat the keeper with an audacious half volley from a seemingly impossible angle that kissed the far post.

With Isak isolated throughout Newcastle chances were at a premium and confined to the counterattack. Joe Gomez blocked an early effort from Lewis Miley, who was played into space on the right by Isak, while Burn had a diving header disallowed for a slight offside against the lone striker after a neatly-constructed break.

Liverpool’s frustration – centred mainly on Taylor’s leniency towards Joelinton – was alleviated minutes after the restart when Salah claimed his 150th league goal. Newcastle were ruthlessly punished on a rare foray into the Liverpool penalty area, with Dominik Szoboszlai finding Díaz in space. The Colombia international surged forward and picked out Núñez unmarked on the right. Núñez, just onside, squared for Salah to reach his latest milestone with a simple tap-in. The watching Roberto Firmino revelled in his former teammate becoming only the fifth player in Liverpool’s history to reach 150 league goals.

Newcastle had offered little as an attacking force yet drew level swiftly, and in style, when Anthony Gordon found himself in space and played a perfectly weighted pass into Isak’s run behind the Liverpool defence. Isak made his first chance of the night count, lifting a delicate finish over Alisson and into the far corner.

• Download the Guardian app from the iOS App Store on iPhone or the Google Play store on Android by searching for 'The Guardian'.

• If you already have the Guardian app, make sure you’re on the most recent version.

• In the Guardian app, tap the Menu button at the bottom right, then go to Settings (the gear icon), then Notifications.

• Turn on sport notifications.

Substitutes have made a huge contribution to Liverpool’s campaign and another arrived with 15 minutes remaining when Jota orchestrated the second. Jota swept down the right before finding Salah, then continued his run into the area where he received the return ball and squared for Jones to convert from close range. Another substitute, Cody Gakpo, added a third when scuffing home an exquisite cross from Salah, who exposed the Newcastle defence with a flick of the outside of his boot.

Botman pulled a goal back for Newcastle when heading home from a corner but Liverpool avoided a nervous finale when Jota went through on goal and was touched as he rounded Dubravka. This time Salah made no mistake from the penalty spot, sending Dubravka the wrong way and Liverpool three points clear.