Bottom-side Sheffield United were relegated from the Premier League after a second-half collapse saw them suffer a heavy 5-1 defeat at Newcastle.
The Blades' 25th league loss of the season ended their miserable return to the Premier League, having won just three games so far, the fewest of any side, and conceded the most goals (97) in a 38-game top-flight campaign.
Chris Wilder's side, who have been relegated with three games left, took a shock lead at St James' Park through Anel Ahmedhodzic's fifth-minute header.
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But the visitors conceded to Newcastle's first shot on target in the 26th minute as Alexander Isak's clinical finish brought the Magpies level.
Sheff Utd then let in four second-half goals in just 18 minutes as Bruno Guimaraes' header sparked a collapse as it was followed by an Isak penalty, a Ben Osborn own goal and a fine finish by substitute Callum Wilson.
Newcastle's come-from-behind win boosts their hopes of European qualification, with Eddie Howe's side just a point behind sixth-placed Manchester United.
Sheff Utd, meanwhile, will be playing Championship football next season as they make an immediate return to the second tier.
How Blades' Championship return was confirmed
Goals had been expected at St James' Park after Newcastle hammered Sheffield United 8-0 at Bramall Lane in September, but it was the Blades who surprisingly flew out of the traps.
A short-corner move saw Ahmedhodzic head in Gustavo Hamer's cross after just five minutes and the visitors then pushed for a second.
But a sluggish Newcastle eventually equalised when Jacob Murphy released Isak in behind and the striker finished superbly.
A chaotic opening half an hour nearly saw Sheff Utd retake the lead as Dan Burn prevented Ben Brereton Diaz's shot from crossing the line after he had rounded Martin Dubravka, before Mason Holgate headed against the woodwork with Andre Brooks smashing the rebound wide.
But the game swung dramatically in Newcastle's favour early in the second half when Anthony Gordon curled a free-kick to the far post for Guimaraes to head home in the 54th minute.
Seven minutes later Gordon won a penalty after being brought down by Holgate and Isak powered home from the spot for his 19th league goal of the season, to put him one behind Cole Palmer and Erling Haaland in the race for the Golden Boot.
Osborn then back-heeled into his own net as he tried to clear at a corner to make it 4-1 in the 65th minute, and Newcastle had a fifth just seven minutes later when Wilson came off the bench to finish smartly.
Sheffield United's misery was complete when a late penalty decision for substitute Alex Murphy's challenge on Jayden Bogle was overturned by referee Tony Harrington after a review at the pitchside monitor.
Wilder: We haven't been good enough all season
Sheffield United boss Chris Wilder speaking to Sky Sports: "We didn't get relegated today - we've been relegated because we haven't been good enough all season.
"We've not been good enough in every aspect of the game. We have to accept that and take that on the chin.
"The old things that came back to haunt us [today]. Physically the league's too powerful for us; they upped the tempo and their game.
"On every front it epitomised what the season's been about - and that we haven't been good enough pre me and after me.
"It's a really poor season and we have to own that, but we'll come fighting and swinging back. There's a lot of work to be done, but we'll be okay."
Howe: I would not swap Isak for anybody else
Newcastle boss Eddie Howe in his post-match press conference: "I think he [Isak] is [world-class], yes, I think he is.
"For me, I think the biggest thing is would I swap him with anybody else? No, I wouldn't. When you look at his age profile and what's to come, you look at his attributes and his qualities, he's some talent.
"He's full of confidence, he looks physically in a really good place and I just think it's a great thing to watch him play currently."
On second-half turnaround: "We knew half-time was going to be important for us. First half, we were - I don't need to tell you - well off it, probably a little bit of tiredness from midweek, the first game in a while and then of course a very quick turnaround.
"It enabled us to settle down a few things and come up with a much better performance."
Opta stats: Blades suffer ninth top-flight relegation
- Indeed, the Blades have suffered their ninth top-flight relegation (as many as local rivals Sheffield Wednesday, also 9), with only five teams suffering the drop from the top division of English football on more occasions; Birmingham City (12), Leicester City (12), West Brom (11), Bolton (10) and Manchester City (10).
- Newcastle scored 13 Premier League goals against Sheffield United this season (the most one team has scored against another in a single campaign in the competition's history) and conceded just once (13-1), the joint biggest aggregate margin of victory (+12) for one team against another in a single Premier League campaign, alongside Manchester City v Watford in 2019-20 (12 goals scored, none conceded).
- Alexander Isak has scored 19 Premier League goals this season, the most by a Newcastle player in a single top-flight campaign since Alan Shearer in 2003-04 (22). Indeed, he's scored in each of his last seven Premier League games at St James' Park with only Andrew Cole (8 in 1993-94) and Alan Shearer (15 in 1996-97) netting in more consecutive home appearances for the Magpies in the competition.
- Sheffield United have conceded 97 goals in their 35 Premier League games this season with only Swindon Town (100 in 42 games in 1993-94) conceding more in an entire campaign in the competition's history.
What's next?
Newcastle face another relegation struggler next as they visit Burnley on Saturday May 4, while Sheffield United host relegation-threatened Nottingham Forest on the same day; kick-offs 3pm.
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