Newcastle United missed out on an opportunity to move into the top four in the Premier League with an abject performance against the now table-topping Southampton.
Che Adams got Saints off to a great start, flashing home a great effort in the eighth-minute and Stuart Armstrong rounded off a dominant display in the 82nd minute.
Southampton came into the game on the back of an injury to their talismanic forward Danny Ings. The Saints managed fine without him but you get the impression that the scoreline would've been much worse for Steve Bruce's side had he featured.
In his place was Theo Walcott, who did everything but score in his first Premier League start at St. Marys.
Story of the game
It took the hosts till just eight minutes in to find the opening goal at St. Marys.
Karl Darlow had made a great stop from a powerful drive from Adams but Miguel Almiron failed to clear the ball and lost out under pressure from Kyle Walker-Peters that allowed Walcott to cross the ball in for Adams, who was not to be denied for a second time. His first-time finish flashed past the United keeper.
Saints continued their dominance and had another chance not long after; Jeff Hendrick was dispossessed far too easily by Walcott who ran forward but fortunately for the Republic of Ireland international blazed his effort high and wide of the goal, ignoring the calls from teammates.
The first action of any note for Bruce's side came with the in-form Callum Wilson driving into the Saints' box but the forward's attempted through ball to Allan Saint-Maximin didn't come off.
The first real chance that the Magpies created fell to Sean Longstaff. An inch-perfect delivery from Jamal Lewis found the head of the 23-year old and he really should have done better, his header went straight into the arms of the grateful Alex McCarthy.
Southampton continued to be the dominant force in the game and Walcott should have scored to give them the two-goal cushion that their play deserved.
A fancy flick from Moussa Djenepo completely split the three Newcastle centre backs but the 31-year old curled his effort wide of the mark.
An awful first 45 minutes was almost capped off when Lewis gave the ball away very cheaply meaning Walcott again had a run at goal with Federico Fernandez having to cynically take the England international out to deny him a run at Darlow's goal, earning himself a yellow card.
New half, same story
Steve Bruce decided not to change personnel at the half time break and clearly, his words of encouragement did nothing to inspire change in his side as it was Southampton who again came out of the blocks much faster.
Inside the opening five minutes of the half, the hosts close to doubling their lead on more than one occasion.
The first of which was a shot from Walcott which came off Fernandez. The deflection completely wrong-footed Darlow but thankfully the ball ended up wide of his goal.
The Toon keeper then made a hash of the resulting corner which saw Jan Bednarek get his goalwards header cleared by skipper Lascelles.
Just seconds later, Oriol Romeu unleashed a venomous strike that was helped on to the crossbar by the fingertips of Darlow.
Newcastle struggled to weather the storm and Darlow was again called upon to make a smarts stop from Bednarek who had got his head on the end of a James Ward-Prowse corner.
It took the Magpies till the 70th minute to register their second shot on goal but Jacob Murphy was unable to replicate his free-kick heroics against Wolverhampton Wanderers and his effort found the Saints' wall.
With a quarter of an hour left on the clock, the hosts had yet another golden opportunity to put the game beyond Newcastle. Stuart Armstrong's pass across the box to Walcott didn't have enough on it and Lascelles was able to get back to make a challenge.
It appeared that the toon captain's last-ditch challenge was a foul on Walcott and Southampton were left scratching their heads as to why VAR chose not to get involved.
Unfortunately, Newcastle's luck soon ran out. The dithering on the edge of their own box was comical and Armstrong was only too happy to nick the ball and slot it into the bottom corner giving Darlow absolutely no chance.
It took 86 minutes for Newcastle to fashion a second shot on target. Substitute Joelinton got his head on a welcoming cross from Lewis and did everything right in his effort but McCarthy pulled off a fine stop to preserve his side's clean sheet.
That was about as good as it got all game for the Magpies and the game finished 2-0 to the hosts.
About as one-sided as a game can possibly be:
Newcastle were second best from the first whistle to the last in what was an alarming performance.
Southampton never had to reach top gear to ease to an easy win over Steve Bruce's men.
The stats from the game paint a damning picture for the Magpies. They had just 39% of the possession and in the whole 90 minutes managed just four shots on goal with just one of them being on target.
Yet again, United conceded a plethora of shots and in the end have a lack of cutting edge from their opponents to thank for not shipping more than two.
If Newcastle's pathetic performance wasn't bad enough, there appear to be fresh injury concerns to key players.
Wilson was taken off on the 78th minute after he had gone down with what appeared to be a muscle injury.
Saint-Maximin also appeared in some discomfort but was forced to see out the rest of the game as Bruce had already used all three changes.
The dynamic duo may have been out of sorts today but have been absolutely crucial for the Magpies this season.
If either of them are set for a spell on the sidelines it would be a huge blow but the upcoming international break could come as a welcome break for Bruce.
Lacklustre midfield missed Hayden
Bruce opted for a midfield consisting of Jeff Hendrick and Sean Longstaff, leaving Isaac Hayden on the bench for a third game running.
There was a complete lack of bite in the midfield and far too many times Southampton ran rings around them.
Neither Hendrick, Sean or Matty Longstaff provided the same cover as Hayden usually offers.
In Hendrick, Newcastle appear to have acquired an immobile midfielder who struggles to successfully pass the ball forwards and both Longstaffs had the look of players returning from injuries.
It is imperative that Hayden comes back into this side sooner rather than later to provide some much-needed balance to the side.
Southampton: McCarthy (GK); Walker-Peters, Vestegaard, Stephens, Bednarek, Romeu, Ward-Prowse (c), Armstrong, Djenepo (Redmond, 74), Walcott (Long,88), Adams. (5-2-3)
Substitutes: Forster (GK); Ramsay, Diallo, Tella, Redmond, Long, N'Lundulu
Newcastle United: Darlow (GK), Murphy (Joelinton 78), Schär, Lascelles (c), Fernandez, Lewis, Hendrick (M.Longstaff,60), S. Longstaff, Almiron, Saint-Maximin, Wilson (Carroll, 78). (5-3-1-1)
Substitutes: Gillespie (GK); Clark, M.Longstaff, Carroll, Joelinton, Hayden, Manquillo