Match ends, Southampton 3, Leicester City 0.
Leicester City remain winless away from home in the Premier League this season after being completely outclassed by Southampton at St Mary's.
Claude Puel's hosts, defeated in each of their past four league games, dominated from the first whistle and deservedly went ahead through James Ward-Prowse's first goal in 22 games.
Ward-Prowse's free-kick helped set up the second for Jay Rodriguez, before Dusan Tadic's late penalty set the seal on a one-sided victory.
Champions Leicester have now gone 11 games without an away league victory this season - having won 11 times on their travels en route to the title. The 37 goals they have conceded in 22 games so far is one more than the total shipped in the whole of last season.
Defeat leaves Claudio Ranieri's side three places and five points above the relegation zone.
Southampton climb to 11th place having comfortably avoided the ignominy of equalling the club's top-flight record of five consecutive defeats, set in 1998.
Foxes' title defence goes from bad to worse
In the corresponding fixture last season, Southampton also took a 2-0 lead into the break before a Jamie Vardy double saw Leicester to a deserved draw.
The point won that day was the seventh the Foxes had earned from a losing position in the first nine games of the season, and was an early clue that they were a little bit special.
"We have fantastic spirit," Ranieri said after that match. "We believe everything could be possible."
Fast forward to this season and the mood in the Leicester camp could hardly be more contrasting.
A few darting runs by Demarai Gray aside, Ranieri's men seldom threatened Fraser Forster's goal, and the two goals conceded before the interval did not come close to galvanising the visitors in the way it had 15 months earlier. Tadic's penalty only compounded their misery.
If Leicester's season is not to become a battle against relegation, they need to start winning quickly - but their upcoming fixtures are far from encouraging.
Four of their next six matches are away from home - including the first leg of their Champions League last-16 tie with Sevilla - while their home games in that period are against Manchester United and Liverpool.
Van Dijk injury sours near-perfect day for Saints
From the moment Ward-Prowse curled a precise finish beyond Kasper Schmeichel from Cedric Soares' low cross, there seemed only one possible outcome.
By the break, the visitors had managed just two touches in the Saints area. The hosts had managed 16 in the other penalty box - one of those a rifled left-footed finish by Rodriguez after a Ward-Prowse free-kick was inadvertently helped on by Leicester defender Robert Huth.
Cruising Saints thought they had added a third after the break when Wes Morgan headed into his own net from a free-kick, only for an offside flag to spare the visiting captain.
But not for long.
A few minutes later, Morgan was flummoxed by the pace of Shane Long, who was hauled down in the area. Referee Michael Oliver rightly pointed to the spot.
Up stepped Tadic to dispatch his first home goal for Southampton in a year.
The loss of centre-back Virgil van Dijk to an apparent ankle injury in the second half will be Puel's only regret, especially in the week that the club lost captain Jose Fonte following his move to West Ham.
Asked about Van Dijk's availability for Wednesday's EFL Cup semi-final against Liverpool, which Saints lead 1-0 after the first leg, Puel said: "We will see tomorrow and the next day. He is an important player for us and I hope he can recover."
Man of the match - James Ward-Prowse (Southampton)
'It is my fault' - what the managers said
Southampton manager Claude Puel: "I think it was a good first half and a good game. We had good management and the possibility to finish the game before we did with a lot of chances.
"A clean sheet, goals - it is perfect for us. It was important to win after the last four we have lost.
"I am pleased to see the players trying to shoot with more responsibility and that Ward-Prowse scored from midfield. That is important and I like this."
Leicester manager Claudio Ranieri: "It was not a good performance. It is my fault. I wanted to change the shape of my teams in the last two matches.
"Against Chelsea, we played three at the back, today a diamond in midfield. Maybe my players didn't understand my idea very well.
"It is important to react. I take responsibility. We have to go back with more desire to get the first away win. I know we try to do our best. At the moment, everything is wrong. I am very frustrated."
Leicester equal unwanted record - match stats
- Leicester's haul of 21 points from 22 games is the joint-worst return for a reigning champion in top-flight history (Ipswich in 1962-63, converted to three points for a win).
- Southampton ended a run of four straight league defeats, picking up their first top-flight win since 18 December (when they beat Bournemouth 3-1).
- Saints scored more than one first-half goal for the first time in the Premier League this season.
- Claudio Ranieri's side have gone 13 away Premier League games without a win, longer than any other side.
- Indeed, it is Leicester's longest winless away streak in the league since 2005 (18 matches).
- Jay Rodriguez scored a Premier League goal at St Mary's for the first time since 27 August.
- Dusan Tadic registered his first league goal at St Mary's in more than a year, since he scored against West Brom on 16 January, 2016.
It's a big week for Southampton, who travel to Anfield for the second leg of their EFL Cup semi-final against Liverpool on Wednesday (20:00 GMT), before hosting Arsenal in the fourth round of the FA Cup on Saturday (17:30). Leicester's next outing is their FA Cup fourth-round tie at Championship side Derby on Friday (19:55).
- 2Cédric Soares
- 17van DijkSubstituted forStephensat 55'minutes
- 23HøjbjergSubstituted forClasieat 73'minutes
- 9RodriguezSubstituted forLongat 80'minutes
- 5MorganBooked at 85mins
- 24MendySubstituted forAlbrightonat 45'minutes
- 20OkazakiSubstituted forMusaat 63'minutes
- Michael Oliver
- Shots on Target
Second Half ends, Southampton 3, Leicester City 0.
Foul by Cédric Soares (Southampton).
Wilfred Ndidi (Leicester City) wins a free kick in the defensive half.
Attempt blocked. Cédric Soares (Southampton) right footed shot from outside the box is blocked. Assisted by Oriol Romeu.
Attempt missed. Shane Long (Southampton) header from the centre of the box is high and wide to the right. Assisted by James Ward-Prowse with a cross.
Attempt saved. Nathan Redmond (Southampton) right footed shot from outside the box is saved in the bottom left corner.
James Ward-Prowse (Southampton) wins a free kick on the left wing.
Foul by Ahmed Musa (Leicester City).
Goal! Southampton 3, Leicester City 0. Dusan Tadic (Southampton) converts the penalty with a left footed shot to the top right corner.
Wes Morgan (Leicester City) is shown the yellow card for a bad foul.
Penalty Southampton. Shane Long draws a foul in the penalty area.
Penalty conceded by Wes Morgan (Leicester City) after a foul in the penalty area.
Corner, Southampton. Conceded by Wes Morgan.
Shane Long (Southampton) wins a free kick on the left wing.
Foul by Danny Simpson (Leicester City).
Attempt missed. Christian Fuchs (Leicester City) right footed shot from outside the box is close, but misses to the left.
Substitution, Southampton. Shane Long replaces Jay Rodriguez.
Corner, Southampton. Conceded by Wes Morgan.
Offside, Southampton. Jordy Clasie tries a through ball, but Dusan Tadic is caught offside.