Jurgen Klopp's side had to come from behind to take all three points thanks to late goals from Mo Salah and Jordan Henderson
IT was a moment of magic.
Mo Salah, eight games without a goal in a Liverpool shirt, streaked through the Southampton defence to take them back to top of the Premier League.
It was, even by his standards, a glorious goal.
He raced across the halfway line and kept on going until he could get his shot away for the edge of the area.
When it left his boot, it cleared Southampton keeper Angus Gunn and came to its final resting place in the back of the net.
When he tore off his shirt to celebrate, he evoked memories of Ryan Giggs in the 1999 FA Cup semi-final when the emotion got the better of him. What a finish.
It is very much a side-note, but Salah is the fastest player in Liverpool history to get to 50 Premier League goal. This was game 69.
He has beaten El Nino by three, getting to the half-century faster than the former Liverpool forward Fernando Torres.
There will be many more to come.
This is another extraordinary twist to the title race because Liverpool were functional and ordinary for so long.
Saints had been ahead after nine minutes, taking advantage of the anxiety and the nervousness in this Liverpool side.
Van Dijk, jeered and booed every time he took a touch of the ball, lost his positioning when Liverpool fell behind.
It was a good goal, laced with conviction when Ryan Bertrand whipped in his cross from the left.
Pierre-Emile Hojbjerg flicked on for Long and Saints striker picked his spot with a masterful finish. What a start.
Long had only scored one goal all season, at Leicester, before he put Saints into this early lead
It is times like this when it is easy to imagine Neil Warnock doing his nut down on his farm somewhere in deepest Cornwall.
He would have been punching the air when Salah and Henderson went on to win it.
They were assured when Liverpool needed somebody to take control of this anxious performance on the south coast.
When Southampton went in search of an improbable second, Van Dijk turned over his own bar when Nathan Redmond crossed.
Saints, encouraged by the “ole’s” from their own fans, suddenly fancied adding to their lead.
It was a pig of a start from Liverpool, struggling to settle into their customary rhythm.
The win against Tottenham, when they needed some crazy luck to win it a minute from time, has taken a lot out of them.
They were leggy in the first half, with the fabled front three spluttering their way through the half.
Angus Gunn saved well from Sadio Mane in the 15th minute and Keita put the rebound wide of the keeper’s post.
He got there in the end.
The equaliser arrived 36 minutes in when Salah, marginally offside, raced behind this Saints defence.
When Southampton pegged him back, the ball fell loose for Andy Robertson to ping in a trademark cross from the left.
Trent Alexander-Arnold, waiting on the other, sent in another cross and Keita headed home.
His first goal has been a long time coming, but a significant one all the same.
Even so, this was below-par Liverpool.
Everybody is watching Friday night football, the game in isolation, to see if they could tolerate the pressure.
It ramps up at this stage of the season because the fixtures are staggered and the games are running out.
They had the chance to pause for thought soon after Keita’s equaliser, heading down the tunnel to talk it through.
He needed a response, to see a bit more energy and conviction from his title-chasers.
Liverpool’s impatient manager made some swift substitutions, sending for the English muscle to get the job done 13 minutes after the break.
James Milner and captain Jordan Henderson came on for Georginio Wijnaldum and Alexander-Arnold.
The big-game expertise, the experience of Milner and the energy of Henderson, was designed to make all the difference.
Liverpool bossed it from there.
Saints manager Ralph Hasenhuttl was right to sense a very, very long last half hour.
He took off Long, with the forward drawing it out so that he could soak up the rapturous applause (and waste some game time) from Saints fans.
They could not contain them.
After Salah streaked through the Saints defence to put them ahead, they finished the job four minutes from time.
Joel Matip sent the ball long for Firmino to run on to down the right.
He cut inside, looking for a Liverpool shirt before cutting back for Henderson to score with an excellent left-footed finish in front of the hordes of travelling fans.
“Liverpool, top of the league” they sang for the final five minutes of this win.
Staying there is the tough bit.
