Responding to manager Jurgen Klopp’s subtle suggestions he needed to consider playing even if not 100% fit, the striker demonstrated masterful finishing ability with two elegant goals to put his team in control after Sadio Mane had headed Southampton into a first-minute lead.
With a hat-trick from Divock Origi — his first goals for the club — and a further finish from substitute Jordon Ibe, Klopp’s team set up a last four clash with Stoke.
“It was a good game — a bad start — but it’s not too often when you can enjoy moments in the last five minutes,” he said.
“It was a new system, the diamond with two strikers, and after 10 minutes it worked.
“(Sturridge) can’t play every game for us. He needs to decide when it’s time to fight and when to rest then he’ll be okay.
“We need a little bit of luck with injuries, but the squad is strong.”
Sturridge started alongside Adam Lallana and Origi in a front three, but it was right-back Connor Randall, making his second senior appearance, who threatened to overshadow the striker’s return for entirely the wrong reasons.
In struggling to prevent Ryan Bertrand’s left-wing cross in the opening minute, Randall set the tone for Liverpool’s sluggish early defending which very nearly cost them defeat. Bertrand’s cross found Mane, and under little pressure the forward headed into the bottom right corner beyond deputy goalkeeper Adam Bogdan.
Randall was almost immediately again under pressure, this time when Dusan Tadic found the space to cross for Victor Wanyama, but despite having similar time and space to Mane from in front of goal, the midfielder headed at Bogdan who made a routine save.
Sturridge had looked worryingly short of confidence with his first touches, when he conceded possession and appeared reluctant to over-extend his fragile physique. With his next, however, he scored Liverpool’s equalising goal.
Joe Allen played the striker into the penalty area with a pass from midfield in the 25th minute, and after hesitating he showed exceptional composure to calmly place the ball across the face of goal and into the bottom right corner beyond Maarten Stekelenburg.
His second goal, four minutes later, was even more impressive. Emre Can showed vision to send the ball into the box with the outside of his boot, and Sturridge lost Cedric before putting Liverpool 2-1 up with a classy first-time shot.
When Moreno’s powerful shot, from the edge of the area following Lallana’s cleared corner, was deflected in by Origi in the 45th minute, Liverpool’s progress into the semi-finals already began to feel secure.
Klopp appeared to feel similarly when, as a precaution, he replaced Sturridge with Ibe in the 59th minute, and had he any remaining doubt it would have vanished only nine minutes later when Origi extended their lead.
When Allen found Ibe, the forward played Origi in with a slide-rule ball into the box, and the now-confident Belgian powerfully struck his team’s fourth into the roof of the net.
Eighteen minutes remained when Ibe, following a left-wing cross from Moreno, sent an equally powerful shot into the back of the net from just inside the area after chesting the ball to control, and even then Klopp’s resurgent team had the time and desire to score again.
Substitute Brad Smith crossed, again from the left, deep into the penalty area towards Origi, and the striker routinely headed in to secure Liverpool’s sixth, and his treble.
Southampton boss Ronald Koeman took his share of the blame for his half-time switch to three defenders, but made it clear his players had created too many problems for themselves.
He said: “The second half is my responsibility. I took the risk and played with three at the back, but when you look at the score at half-time — 1-3 — it’s not good.
“I was disappointed with the way we did our defending today. The defence starts in front but the home team’s performance defensively in the first half was not good.”
Everton v Manchester City, Stoke v Liverpool.
First legs to be played in the week commencing January 4, 2016. The second legs are in the week commencing January 25.
Stekelenburg, Cedric Soares (Ward-Prowse 63), Caulker, van Dijk, Bertrand, Clasie (Long 63), Wanyama, Tadic, Mane, Steven Davis (Romeu 77), Pelle.
Bogdan, Randall, Skrtel, Lovren, Moreno (Smith 77), Can, Lucas, Allen (Henderson 74), Lallana, Sturridge (Ibe 59),Origi.