Daniel Sturridge scored twice on his return from injury and Divock Origi opened his Liverpool account with a hat-trick as Jurgen Klopp's men stormed into the League Cup semi-finals with a 6-1 demolition of Southampton.

Ronald Koeman's team started in sensational fashion at St Mary's Stadium as Sadio Mane headed them into a first-minute lead and there was little indication of the thrashing to come as Liverpool initially responded in a listless fashion. 

All that changed when Sturridge, making his first start since the October Merseyside derby that heralded the end of Brendan Rodgers' Anfield reign, fired them level after 25 minutes.

Sturridge soon added a second courtesy of a showreel assist from Emre Can and Origi turned in an Alberto Moreno shot in the final minute of the half to conclude a devastating spell.

If there was a touch of fortune about Origi's first, his second arrived in more emphatic fashion – crashing home from the right-hand side of the area via the inside of the crossbar – and substitute Jordon Ibe got in on the act before the Belgian striker nodded in to claim the matchball in the 86th minute.

It left the home faithful in markedly different spirits to when they led after 39 seconds thanks to Mane stealing in front of Moreno to bury Ryan Bertrand's excellent cross.

Southampton continued to have joy down the Liverpool right and Adam Bogdan kept out Victor Wanyama's header from Dusan Tadic's fifth-minute centre.

Liverpool's young right-back Connor Randall was the man under fire and he collected an early booking for pulling back Tadic – Steven Davis curling the resulting free-kick over.

Klopp's side were struggling to establish themselves as an attacking force midway through the half, but Sturridge turned the contest on its head with two goals in the space of four minutes.

The England striker raced on to Joe Allen's lofted throughball, made light of a loose first touch by skipping past Steven Caulker with a stepover and drilled a left-footed finish beyond Maarten Stekelenburg.

A sumptuous piece of play from Can crafted Sturridge's second, the Germany international creating space with a cute turn and curling a pass over the Southampton defence with the outside of his right foot for the Liverpool forward to net clinically on the half-volley.

There was further misery for a stunned Southampton as Moreno's drive from a partially cleared corner received a faint touch from Origi as it fizzed past Stekelenburg.

Graziano Pelle, back in the Southampton side following suspension, drew a 50th-minute save from Bogdan under pressure from Martin Skrtel before St Mary's old boy Dejan Lovren blocked a shot from the continually lively Mane.

Sturridge departed to a rapturous ovation from the away end when Ibe took his place in the 59th minute, while Southampton substitute Shane Long almost made an instant impact by glancing a header wide.

But Southampton's lingering hopes of a comeback were extinguished in the 68th minute, with Origi latching on to Ibe's slide-rule pass to leave Stekelenburg with no chance.

Ibe showed similar precision in the 73rd minute, chesting down Moreno's cross to find a low finish and Origi converted Brad Smith's centre to seal Liverpool's place in the semi-finals of a competition they last won in 2012.