The best move ultimately counted for nothing, but in those breathtaking 20 seconds you saw the wonderful possibilities that exist for them.
Early in the second half, Liverpool found themselves under pressure on the edge of their own area and Southampton's players were intent on maintaining their press.
Then, Alisson Becker played a short pass to centre back Joe Gomez, who in turn zipped it sideways to defensive colleague Virgil van Dijk.
Liverpool shouldn't neglect the FA Cup in what is set to be their greatest ever campaign
One false move, one heavy touch and Southampton would have been in, but those in red went into pinball mode, passes pinging back and forth, left and right.
Out of tight spaces they went, faster and faster up the field until Mohamed Salah slid a shot into the Kop End net.
To the Egyptian's frustration, his run on to Roberto Firmino's pass was wrongly timed by a fraction and an offside flag cut short the celebrations.
The prolonged and thunderous applause, however, did not subside. Quality needs recognition and this Liverpool team is as special as any that have gone before.
Jurgen Klopp's side may come to regret it if they don't go for glory in the FA Cup this season
Be under no illusion they have the capacity to make this the greatest season in the club's 128-year history. They have collected the European Super Cup and Club World Cup. The Premier League is destined to be gathered in spring, because despite the best efforts of their rivals, Liverpool are over the hill and far away.
Yet three pieces of silverware could conceivably become five and that brings us to the issue of the FA Cup. We know it is the lowest on Liverpool's list of priorities, but is it so low that it is almost inconsequential?
Jurgen Klopp and his senior players started a week's break immediately after Southampton had been skewered 4-0 and the responsibility for trying to set up a fifth-round tie has been bestowed on Under 23 coach Neil Critchley, along with a raft of promising novices.
Whether the full squad should be resting is open to debate. Do Joel Matip and Dejan Lovren, who require games after injuries, need to be absent? What about Naby Keita and Takumi Minamino, who would welcome the chance to gain rhythm?
Players such as Takumi Minamino would benefit from featuring in the replay vs Shrewsbury
As it is, Liverpool's kids might be good enough to see off a team who are 16th in League One, but equally they could fall short. If they get through to a fifth-round date with Chelsea at Stamford Bridge in four weeks, Klopp is unlikely to change his policy of giving youth its head.
It is admirable but it is not realistic to think that a team with such inexperience