It is an Anfield ritual. Before kick-off, the loudest ovation tends to go to the last Liverpool player introduced to the crowd. Normally it is the slot reserved for Luis Suarez. Here, sensing the mood, the announcer changed the usual running order. Welcome back, he said, to No. 21: Lucas Leiva.
It was a sign that a two-year transformation from scapegoat to saviour was complete. Once the unconvincing understudy to Javier Mascherano and Xabi Alonso, Lucas is now irreplaceable in his own right. After three months on the sidelines, a thigh injury underlining the importance of the man who liberates others to do the more glamorous jobs, Liverpool relished his return.
When he exited, 88 minutes in and replaced by Jamie Carragher, the applause was still louder. It was a tribute to the inconspicuous excellence of a quietly important player. While Roy Hodgson and Kenny Dalglish grew to appreciate Lucas' merits, Brendan Rodgers may be more enthusiastic about his attributes. The midfield anchorman can be the pivotal player for the Northern Irishman's style of play. "I thought he was excellent," said the Liverpool manager. "He offers the team great stability."
There was nothing spectacular from Lucas, but then there rarely is. He is a specialist at the safe, sensible ball and the timely interception. With his passing and his positioning, he provided the platform for dominance in a win that was more comfortable than the scoreline suggested.
While Liverpool possessed the ball for almost two-thirds of the game and had nearly three times as many shots as their visitors, the immediate impact of Lucas' return was to relieve Steven Gerrard and Joe Allen of some of their defensive duties. The greater beneficiaries of the midfield control, however, were the overlapping full-backs.
Even after reverting to his more familiar role following his recent reinvention as a winger, Jose Enrique displayed his adventurous side. On the other flank, meanwhile, Glen Johnson was rampaging and rampant.
When, a few weeks ago, Rodgers had bracketed Johnson alongside Daniel Alves as the world's best right-back, eyebrows were raised. If that was hyperbole, what can be said with rather less risk of contradiction is that Johnson is among the finest when foraying forward. He was certainly too good for the inexperienced, and exposed, Luke Shaw. It has been a familiar problem for Southampton that the full-backs are not afforded enough cover.
It came at a cost, even if the only goal was the indirect consequence of a set-piece. Suarez struck the bar with a free kick, Johnson retrieved the rebound and crossed for Daniel Agger to score. "A free header in the penalty area," rued Nigel Adkins, who thought Southampton would reach the break on level terms.
As he admitted, they might not have deserved to. "We had nowhere near the possession of the football we usually do. Liverpool's movement was very good." It was in every respect bar one: they struggled to manoeuvre the ball into the net.
Jonjo Shelvey struck the post with a ferocious strike, Jose Enrique had a golden chance and Suarez came close time and again. But when the ball kept staying out, he resorted to the illegal. He was castigated for his impromptu attempts at goalkeeping in the 2010 World Cup quarter-final against Ghana and his handling skills remain.
When Gerrard crossed, Suarez tried to punch it in. Referee Michael Oliver cautioned him. "I didn't see it but I don't think it was cheating," said Rodgers, providing conflicting explanations. Either way, the result is that the sole fit senior striker in the Liverpool squad will be banned for the trip to West Ham. A fifth booking of the campaign was the price paid for his deception and no sooner had Suarez's form earned him complimentary comments, then his conduct will probably bring renewed criticism.
Now Liverpool face the task of winning at Upton Park, one which confounded their former manager Rafa Benitez, without a specialist centre-forward but at least knowing the defence will be shielded all the better by the returning Lucas. Exit the finisher, enter the fulcrum.
MAN OF THE MATCH: Glen Johnson. A terrific performance. With Raheem Sterling roving around intelligently to create space for the marauding full-back, Johnson served as a one-man right flank and set up the goal.
LIVERPOOL VERDICT: Impressive, even if neither Gerrard nor Allen had his finest game. Enrique and Johnson both attacked with relish while Shelvey, though not a natural winger, again illustrated that he gets in goalscoring positions. He may be tasked with playing as the false nine at Upton Park. The one upside of Suarez's ban is that presumably he will be taken to Udinese for the decisive Europa League game.
SOUTHAMPTON VERDICT: When Steven Davis was brought on, the PA announcer, confusing his teams in white, said it was a substitutions for Swansea. Cue a chorus from the Kop of: "Are you Swansea in disguise?" On the day Michael Laudrup's team won at Arsenal, they really weren't. They were fortunate not to suffer a heavier defeat with Adkins admitting he was trying to turn a naturally adventurous team into a counter-attacking side for the day. Lifelong Liverpool fan Rickie Lambert was the only man to threaten a goal but his shots thudded into the advertising hoardings.