Five goals in a rampant first half earned Tottenham a stunning victory at St Mary's Stadium and ended the tenure of Southampton boss Russell Martin.

A strike inside 40 seconds from James Maddison settled any pre-game nerves for Spurs manager Ange Postecoglou, the England midfielder tucking home from Djed Spence's clever pass.

Against a woefully open Saints defence, Tottenham's free-scoring attackers cleaned up, Son Heung-min firing past Alex McCarthy and Dejan Kulusevski tapping in from close range inside the first 15 minutes.

Amid angry boos from the stands, Martin's response was to abandon his four-man defence and revert to a back three, withdrawing a distraught Kamaldeen Sulemana straight after the third goal.

And yet it did not work as a shell-shocked Southampton were hit on the break by Son once more and he teed up Pape Sarr to dance through two half-hearted challenges and slot into the net.

Spurs captain Son was denied three more times by McCarthy before Maddison smashed into the top of the net from a ridiculous angle deep into first-half stoppage time.

With Spurs fans delirious in the away end, some Southampton supporters took to the exits early, rightly anticipating little hope of a miracle comeback.

Matheus Fernandes did think he had pulled one back in the 80th minute but his header was ruled out for offside.

The result leaves Saints nine points from safety and guaranteed to be bottom at Christmas. Meanwhile, Tottenham are up to 10th, entrenched in a congested mid-table where just three points separate eight teams.

This game was the nadir of a bleak return to the Premier League for Southampton.

Championship play-off winners back in May, Martin's style of play – and the Saints players – have found it a formidable step up with just 11 goals scored in 16 games and 36 shipped at the other end.

With senior players Alex McCarthy and Jan Bednarek available again, Martin went for a four-man defence against supposedly fatigued and under-pressure opponents.

It was an experiment he ditched after 15 minutes as his bedraggled players wilted in the headlights of the Spurs juggernaut.

It did not work. Tottenham were a constant threat, first to every loose ball and rapier-like through a flimsy Southampton midfield.

With their eighth shot on target of a brutally one-sided first half, Maddison made it five - cutting inside a flailing defender and blasting into the top corner.

Martin did not even see it – he had headed for the dressing room early to meet his players.

Saints showed spirit after the break, helped by some remarkable positive support from the stands and the probing of Tyler Dibling, but it was too little, too late.

With just five points from their first 16 games, Southampton have been far too easy to play against. Martin paid the price with his job, and his successor will have to find a solution fast to stand any chance of rescuing what seems an increasingly doomed season.

After a very noisy week at Tottenham, it must have been nice for Postecoglou to see the spotlight turned on his opposite number.

The Spurs boss openly questioned some of his players on Thursday, specifically Timo Werner, after a difficult night against Rangers in the Europa League.

He doubled down on his criticism on Friday and made five changes for this game, albeit some of those enforced due to suspensions for midfield pairing Yves Bissouma and Rodrigo Bentancur.

Indeed, Tottenham have lost three and drawn one of the four Sunday games they have played after Thursday matches, but they got off to a hot start and never looked back on the south coast.

In many ways, Southampton played into their hands – more open than a shopping centre at Christmas time – but the Spurs attackers took full advantage.

On this form, a forward line of Maddison, Kulusevski, Son and Dominic Solanke is one of the best in the Premier League and they feasted on the space afforded to them.

They are second top scorers in the Premier League with 36 goals in 16 games and have an impressive +17 goal difference, while Son's two assists here moved him level with Darren Anderton as Tottenham's joint-leading provider in their Premier League history at 68.

Putting to bed inferior opponents in this fashion will go a long way towards helping improve their league position.

After all, they are only five points off the top four.