Anthony Martial wasted no time in writing himself into Manchester United folklore as he stepped off the bench to score a stunning debut goal against Liverpool.
Twenty-one minutes after his introduction, the £58million deadline-day signing turned Martin Skrtel twice before rolling the ball past Simon Mignolet to wrap up a 3-1 win for Louis van Gaal's side.
Christian Benteke had found the net with an acrobatic and arguably superior goal moments earlier, but Martial stole the show after his maiden strike.
Kelechi Iheanacho maintained Manchester City's 100 per cent start to the season with a late winner over Crystal Palace at Selhurst Park - and moved Manuel Pellegrini's men 11 points clear of ailing Chelsea.
The Nigerian substitute had been on the field less than a minute when he fired home in the first minute of injury time after following up when Palace keeper Alex McCarthy spilled an initial effort from Samir Nasri.
And the importance of Iheanacho's strike was underlined by the continuing travails of Jose Mourinho's Chelsea who had earlier slipped to their third defeat in five games courtesy of Steven Naismith's hat-trick in a 3-1 win for Everton at Goodison Park.
Alan Pardew's men will feel aggrieved not to leave with something after largely frustrating their opponents for much of the afternoon and coming close to grabbing the lead themselves through Jason Puncheon's first-half header.
And City's joy was tempered by the sight of Sergio Aguero limping off in the 24th minute with an apparent right knee injury following a challenge by Scott Dann, leaving the Argentinian a doubt for Tuesday's Champions League clash with Juventus.
Barclays Prem
W Brom 0 - 0 So'ton
Man Utd 3 - 1 Liverpool
Watford 1 - 0 Swansea
Norwich 3 - 1 B'mouth
Arsenal 2 - 0 Stoke
C Palace 0 - 1 Man City
Everton 3 - 1 Chelsea
But City's problems are nothing compared to those afflicting the defending champions who were left reeling by an early double from Naismith, who was a ninth-minute replacement for the injured Muhamed Besic.
Mourinho's men clawed a goal back with a fine strike from Nemanja Matic before half-time, but Naismith rewarded the hard-working Toffees by wrapping up victory - and his own superb hat-trick - in the 82nd minute.
Arsenal took advantage of Palace's late loss to move up to second in the table but the Gunners were afflicted by familiar problems in front of goal as they ground out a 2-0 win over Stoke at the Emirates Stadium.
The hosts missed a series of first-half chances with Stoke keeper Jack Butland pulling off a series of outstanding saves before he was finally nutmegged by Theo Walcott who grabbed the opener on the half-hour.
More heroics from Butland to deny Walcott and Mesut Ozil kept Stoke in the game before substitute Olivier Giroud headed home from a Santi Cazorla free-kick in the 85th minute to seal the points for Arsene Wenger's men.
Saido Berahino received a mixed reception as he returned as a second-half substitute in West Brom's goalless draw with Southampton at The Hawthorns.
Barclays Prem
1 Man City 15
2 Man Utd 10
3 Arsenal 10
4 C Palace 9
5 Everton 8
6 Leicester 8
7 Swansea 8
8 Norwich 7
9 Liverpool 7
10 West Ham 6
11 So'ton 6
12 Watford 6
13 W Brom 5
14 A Villa 4
15 B'mouth 4
16 Chelsea 4
17 Tottenham 3
18 Newcastle 2
19 S'land 2
20 Stoke 2
Berahino replaced former Saint Rickie Lambert in the 54th minute but could not break the deadlock, with Jay Rodriguez missing the visitors' best chance and the Baggies begging in vain for a first-half penalty after Matt Targett pulled down Calum McManaman in the box.
Ten-man Watford claimed their first win of the season with a 1-0 success against Swansea despite Valon Behrami's 64th minute red card.
The Hornets went ahead just before the hour-mark when Odion Ighalo fired home from a Troy Deeney knock-down to give his side their first home goal of the campaign.
And Watford held on relatively comfortably to the points despite their numerical disadvantage due to Behrami's straight red for pulling down Andre Ayew.
Alex Neil's Norwich claimed a convincing 3-1 win over Bournemouth at Carrow Road thanks to another fine performance from Wes Hoolahan.
Hoolahan set up Cameron Jerome's 35th-minute opener then added a second himself early in the second half. Matt Jarvis marked his debut with the Canaries' third on 67 minutes before the Cherries grabbed a late consolation from Steve Cook.