A super goal from Danny Ings was enough for Southampton to beat lacklustre Tottenham 1-0 and continue their recent unbeaten run.
Saints looked like the more energetic side from the first whistle and went ahead when Ings produced a confident, sweeping finish in the 17th minute as he enjoys his best scoring season.
- Harry Kane suffers hamstring injury
- Jose Mourinho: I was rude to an idiot
- Premier League Table | Fixtures | Top scorers
Tottenham looked short of ideas at St Mary's and their poor performance was compounded in the 73rd minute. Harry Kane, having had a goal ruled out for offside, was taken off with a suspected hamstring injury, before manager Jose Mourinho was booked after entering the Southampton technical area following the disallowed goal.
Mourinho confronted Southampton's goalkeeping coach Andrew Sparks over a perceived delay and time taken to substitute Ings for Michael Obafemi in the 76th minute, with the Portuguese saying after the game: "I was rude, but I was rude to an idiot."
The result catapults Southampton into 11th place, having taken 10 points from their four games over the festive season, while Tottenham remain in sixth with just four points over the same period.
How Southampton breezed past Spurs
It was a thoroughly entertaining first half, and Southampton almost took the lead inside three minutes. Ryan Bertrand swung a wonderful cross in from the left, but Cedric Soares could only nod the delivery across the face of goal. Not long after, Kane saw his first shot blocked by the leg of Jan Bednarek before his second - also diverted goalwards by Bednarek's calf - was well saved by Alex McCarthy.
Southampton continued to see the better of the play and, in the 17th minute, took the lead with a superb goal from Ings.
Jack Stephens pinged a wonderful ball forward, which the Southampton striker controlled with a fine first touch. He drove into the box, leaving Toby Alderweireld on his knees as Ings pinged the ball over his head, before powering home past a rooted Paulo Gazzaniga for his 13th Premier League goal of the season.
Southampton: McCarthy (7), Cedric (6), Stephens (7), Bednarek (7), Bertrand (7), Armstrong (7), Ward-Prowse (7), Hojbjerg (8), Redmond (7), Djenepo (7), Ings (8).
Subs used: Long (6), Obafemi (5), Romeu (n/a).
Tottenham: Gazzaniga (6), Aurier (6), Alderweireld (6), Vertonghen (6), Sessegnon (6), Ndombele (6), Sissoko (6), Eriksen (7), Moura (7), Kane (6), Alli (6).
Subs used: Lo Celso (6), Lamela (5).
Man of the match: Pierre-Emile Hojbjerg.
But Tottenham could have equalised before the break. Kane again hammered an effort goalwards, forcing a spilled save from McCarthy.
Dele Alli came racing in to try and slot the loose ball home, but was sent over by the onrushing goalkeeper. A brief VAR review ruled out the possibility of a penalty with McCarthy getting plenty of the ball. From the resulting corner, Alli glanced the ball into Jan Vertonghen's path but the defender fired his shot over the crossbar from close range.
Southampton had a huge penalty appeal turned down early in the second half. Bertrand's cross smacked against the arm of Alderweireld with Mike Dean initially waving away the claims. VAR reviewed the incident and agreed with the on-field decision, with Alderweireld deemed not to be in an unnatural position and unable to move as Bertrand's fierce drive hit him at close range
- Southampton made two changes with Sofiane Boufal and Che Adams dropping out for Stuart Armstrong and Moussa Djenepo.
- Tottenham also made two changes with Lucas Moura and Moussa Sissoko coming in for Juan Foyth and Giovani Lo Celso.
Tottenham thought they had scored in the 73rd minute when Kane poked home a Christian Eriksen free-kick, but the linesman instantly flagged for offside. The Tottenham captain immediately had his hand up afterwards, indicating that he needed to be substituted, as he felt the back of his left hamstring. As he hobbled down the tunnel, VAR was checking his goal, but soon agreed with the offside decision.
In the aftermath, Tottenham manager Mourinho went over to the Southampton bench and there were some cross words exchanged between the Portuguese and Saints coach Sparks before he went back to his own dugout. Referee Dean was soon over to show Mourinho a yellow card, which he openly accepted.
Both sides went close in the final 10 minutes. Substitute Shane Long rose above Vertonghen, but just headed a James Ward-Prowse corner delivery wide of the post. At the other end, Lucas Moura had two bites of the cherry, the first being blocked by Nathan Redmond before the second hit Bertrand on the arm before going wide. VAR also checked it for a penalty appeal but nothing was given.
Southampton manager Ralph Hasenhuttl: "It's a fantastic start to the year - a really intense game - and our best performance at home so far. We were so aggressive, so committed, very difficult to create chances against this team.
"Everyone was doing his best job. We can score always but the key was the work against the ball and the clean sheet. This is the biggest difference from two months ago.
"Ings is in an unbelievable moment when he has a chance he scores, to do what he did today you need a lot of self-confidence and he is full of confidence."
Tottenham manager Jose Mourinho: "I think the yellow card is fair because I was rude, but I was rude to an idiot. And for some reason, I was rude, but I was and because I was I deserve the yellow card.
"For me the referees are not the referees. I think the VAR should change their name because Video Assistant Referee is not true.
"It should be VR - Video Referee - because they are the referees. It is strange. You see the refs on the pitch and they are not the refs, they are the assistants.
"What I know is Dele Alli penalty was a penalty and the VAR didn't interfere. He then interfered in a penalty that from 75 yards away I knew was not a penalty. But they let the VAR analyse it to try to make us blind about the penalty that was a penalty.
"Sometimes it goes in our favour like at Norwich and sometimes against us. But the direction it is taking us in is really really wrong."
Soccer Saturday pundit Paul Merson:
"Have they improved under Mourinho? Not at all. They were poor today. It looked like a team that didn't know what they were doing. If something was going to happen, they were going to fall over it. It was poor. I don't see them getting into the top four the way they are playing.
"Kane's injury could be four to six weeks and it's worrying times for Tottenham. Southampton were the better team. I didn't know what Tottenham were doing.
"If l were Tottenham, l would be going for Danny Ings in this transfer window. He's a proper footballer and his goal was outstanding. He ticks all the boxes for Tottenham. He has an all-round game. I would get him because you know that Eriksen is going to go."
Analysis: Injuries will intensify debate
Sky Sports' Nick Wright:
'Premier League managers from Jose Mourinho to Pep Guardiola have been queuing up to criticise the packed festive fixture schedule recently and there was more evidence of why on New Year's Day as a string of players from clubs up and down the table succumbed to injury.
'Kane was the most high-profile, suffering a suspected hamstring problem on his fifth start in 17 days, but Tottenham were not the only ones affected and, with many Premier League sides already coping with long absentee lists, the debate over the festive fixture schedule is sure to intensify following the third round of Premier League games in just six days.
'The Premier League has introduced a February winter break this season, which will take place across two weekends, but that is little comfort to sides already decimated by fatigue-related injuries. Leicester boss Brendan Rodgers summed up the views of his counterparts last week. "It's 'Let's pretend to have a break'," he said. "It's disappointing to say the least."'
Man of the match - Pierre-Emile Hojbjerg
He may not have been one of the flair players like Ings or Redmond, but Southampton captain Hojbjerg's contribution on Wednesday cannot be underestimated. As Tottenham gave away possession countless times in midfield, Hojbjerg was there to take advantage and set Southampton on their next attack.
His stats make for impressive reading too. He made a total of 51 passes - 35 of which were successful - and made 31 of those in the opposition half which demonstrates his importance to Southampton's impressive performance. He also gained possession 14 times and made three interceptions as he drove the Saints to another victory.
- Southampton have won two of their last three Premier League clashes with Tottenham (L1), after winning just one of the 13 before that (D2 L10).
- Tottenham have kept only one clean sheet in 11 games under Jose Mourinho in all competitions.
- Only Jamie Vardy (17) has scored more Premier League goals this season than Southampton's Danny Ings (13).
There a brief Premier League break now as the FA Cup third round takes centre stage. Southampton will host Huddersfield on Saturday (kick-off 3.01pm) before travelling to Leicester on Saturday 11 January in the league (kick-off 3pm).
Live Premier League
For Tottenham, they will travel to Middlesbrough on Sunday (kick-off 2.01pm) before a huge clash against Liverpool on Saturday 11 January, live on Sky Sports (kick-off 5.30pm).