Brendan Rodgers’ impressive Foxes registered five first-half goals at St Mary’s en route to inflicting the heaviest defeat in Saints’ 134-year existence and move second in the table.
Strikes from Ben Chilwell, Youri Tielemans and James Maddison completed an astonishing scoreline as City emulated Manchester United’s 9-0 win over Ipswich in March 1995.
During a history-making night on the south coast, Saints defender Ryan Bertrand became the first top-flight player sent off following a VAR review after a dangerous lunge at Perez in the build-up to Chilwell’s 10th-minute opener.
The early dismissal undoubtedly had a significant impact on the home side’s fortunes but it could not excuse the embarrassing – and record-breaking – capitulation which followed.
Southampton’s previous worst defeats on home soil were 6-0 reversals to Plymouth in 1931 and Brentford in 1959. The thumping loss also surpassed three 8-0 defeats on the road, the most recent of which came against Everton in 1971.
At his pre-match press conference, Southampton boss Ralph Hasenhuttl had called his side to grind out a “dirty win” to give their success-starved home fans a first win on home soil since mid-April.
But their hopes of doing so were dealt a hammer blow during a dramatic couple of minutes which saw them fall behind and reduced to 10 men.
Left-back Chilwell claimed the goal, just the second of his professional career, finishing first time on the rebound after Angus Gunn pushed away Harvey Barnes’ initial effort.
With the Foxes still celebrating, Saints’ misery was quickly compounded as referee Andre Marriner was advised by the VAR to show a deserved red card to Bertrand for desperate studs-up lunge at Perez in the build-up.
Replays of the challenge left Southampton with little to complain about and the game quickly ran away from them in remarkable fashion.
Leicester, who had dominated possession before Bertrand’s dismissal, doubled their advantage in the 17th minute when Tielemans fired a low shot past Gunn after Yan Valery had inadvertently diverted the ball into his path.
Boos rang around the ground just seconds later when Perez broke into the box by stylishly exchanging passes with Tielemans before skidding a low shot off the sodden surface and past Gunn at the near post.
Imposing Leicester were in no mood to take pity on their stunned hosts and, after Valery tested Foxes keeper Kasper Schmeichel during a rare home attack, they turned the screw with two more first-half goals.
Perez emphatically claimed his second in 39th minute by connecting with Chilwell’s deep cross from the left to thump a close-range half-volley into the roof of the net.
Former England striker Vardy brought more jeers from the stands in the final minute of the half by easily slipping inside Maya Yoshida and smashing the ball beyond Gunn.
The jubilant away end showed little sympathy with chants of ‘Oh when the Saints go marching out’ as Southampton fans left their seats in droves for much-needed refreshment or, in many cases, an early exit.
Damage limitation was very much on the mind of Hasenhuttl as he brought on defenders Kevin Danso and Jack Stephens at the break.
The alterations had little, if any, impact. Perez, who hit a hat-trick for Newcastle against Saints last season, claimed his treble by calmly chesting down a Barnes pass and volleying beyond Gunn in the 57th minute.
Second later the ball was in the same net again as the unmarked Vardy headed home a Chilwell cross.
Saints, who briefly threatened to pull one back through Nathan Redmond, had yet more torture to endure.
Maddison expertly curled home a 25-yard free-kick five minutes from time, before Vardy claimed his third from the penalty spot after being brought down by Jan Bednarek in stoppage time.
- Leicester City have earned 20 points from their opening 10 Premier League games of 2019-20, one more than at the same stage of their title-winning 2015-16 campaign (19) and their joint-most ever in a top-flight season, along with 1930-31 (adjusting to 3 points/win).
- This was Southampton’s biggest ever defeat as an English league side in all competitions in their history.
- Leicester recorded the joint-largest ever margin of victory in Premier League history, alongside Manchester United’s 9-0 win over Ipswich at Old Trafford in March 1995.
- Leicester recorded the biggest-ever victory by an away side in an English top-flight league match in the 131-year history of the Football League.
- Southampton have had a player sent off in each of their last three league meetings with Leicester, becoming the first side to receive a red card in three or more consecutive Premier League games against a single side since Newcastle against Liverpool in May 2014 (four in a row).
- Leicester became only the second team in Premier League history to establish a five-goal lead in the first half of an away game in the competition, after Manchester City against Burnley in April 2010 (also 5-0).
- Leicester City scored three goals in the opening 19 minutes against Southampton, the fastest they have gone 3-0 ahead in a Premier League match since April 1998 against Derby County (eight minutes).
- Leicester have become only the second side in Premier League history to have two players score a hat-trick in the same game (Perez and Vardy), after Arsenal in May 2003 – also against Southampton (Pennant and Pires).
- Leicester’s Ayoze Perez has become the first player to score a hat-trick in back-to-back Premier League appearances against a single opponent since Luis Suarez against Norwich City in September 2012. His second goal tonight was his 50th in all competitions for English clubs.
- Leicester’s Ben Chilwell scored just the second goal of his professional career in his 106th appearance in all competitions; his only previous strike came in a 6-1 defeat to Spurs in May 2017.