The pressure on Newcastle manager Alan Pardew ratcheted up a notch at former club Southampton, where Graziano Pelle inspired Ronald Koeman's new-look side to a dominant victory.
A recent poll showed 85 per cent of supporters did not want the Magpies manager to stay, and those dissenting voices were given further ammo by a tepid performance at St Mary's.
Summer signing Pelle's brace was complemented by goals from Jack Cork and Morgan Schneiderlin as Southampton ran out deserved 4-0 winners at St Mary's, where calls for Pardew's head punctuated a game Newcastle owner Mike Ashley was there to see first-hand.
The sportswear magnate ended speculation that he is ready to sell the club on the eve of the match, although that will only sharpen the focus on the managerial position after a defeat that leaves them in the relegation zone.
The possibility of United winning their first match of the season never looked likely after a bright Southampton start in which Pelle headed home with just six minutes on the clock.
The Italian soon added another from close range - his fourth in three matches in all competitions - with Cork's first league goal for the club and a late curling effort from Schneiderlin increasing the pressure on Pardew.
An angry fan had to be apprehended after running on to the pitch at the end of a game which looked to be going only one way after just 23 seconds.
Attempting to clear a Fabricio Coloccini backpass, Tim Krul's clearance struck Shane Long but, fortunately for the Newcastle goalkeeper, went wide.
It was a warning shot the visitors failed to heed as, after some last-ditch challenges and a penalty appeal from Long, Saints opened the scoring after six minutes.
Meeting a Ryan Bertrand cross from the left, Pelle, the man charged with replacing talisman Rickie Lambert, impressively powered a header into the top-left hand corner.
The Italian was clearly keen to add to his tally and showed impressive inventiveness to hook goalwards from an acute angle, forcing an unorthodox save from Krul.
Pelle's second eventually came in the 19th minute, though, courtesy of his own miscued strike. The 29-year-old attempted to volley a Mike Williamson clearance but it went so wide it landed at the feet of Dusan Tadic, who ignored offside appeals to square the ball for the frontman to tap home.
"We want Pardew out" soon echoed around St Mary's, with both sets of fans chanting "you're getting sacked in the morning".
It took 26 minutes for Newcastle to call their former goalkeeper into action and when they did Fraser Forster showed why Saints forked out B£10million for his services, denying a close-range, first-time Moussa Sissoko effort.
The England international also had to be alert to a fizzing Jack Colback drive as United improved towards the end of the first half, although a deflected Yoan Gouffran effort was the only chance of note they could muster.
It led to boos at half-time from the vocal travelling support, who impressively put their troubles behind them to help welcome Southampton fans' favourite Francis Benali as he ended a 21-day, 1,000-mile run for Cancer Research.
The former defender managed just one league goal over more than 300 appearances for Saints so it was somewhat apt that another long-serving player would break his scoring duck.
Cork scored in the recent Capital One Cup tie at Millwall but had failed to net a league goal for Saints over two spells with the club until latching on to a deflected Steven Davis ball, rounding Krul and slotting home.
In case their chanting had not got across, with 20 minutes remaining a section of Newcastle fans displayed a banner with 'Pardew out' scrawled on it.
It was a period in which the visitors came close to scoring on several occasions, with Emmanuel Riviere and Colback somehow failing to turn home before Forster denied a Gouffran header.
Florin Gardos joined fellow debutant Toby Alderweireld for the final few minutes, which saw Schneiderlin add extra gloss with a wonderful curling effort in stoppage time.