New Manchester City signing Erling Haaland marked his Premier League debut with a double as the champions began their title defence with a clinical 2-0 victory over West Ham United at the London Stadium on Sunday.
Meanwhile, Manchester United suffered a 1-2 defeat to Brighton & Hove Albion at Old Trafford.
Pep Guardiola's City were awarded a penalty after 36 minutes when Haaland charged past the West Ham defence to latch onto a through ball and take it around Alphonse Areola before being fouled by the substitute goalkeeper.
The Norwegian striker stepped up to convert the spot kick, his cool finish sending Areola the wrong way to give City a deserved lead after an utterly dominant first half in which West Ham were rarely able to venture from their own box.
City midfielder Kevin De Bruyne then defended a series of crosses before slipping through a delightful pin-point pass to Haaland, who timed his run to perfection and slotted home with a fine left-footed finish in the 65th minute.
West Ham forward Michail Antonio had headed wide in the opening stages and De Bruyne easily cleared Jarrod Bowen's free-kick just before halftime, but the hosts struggled to make their mark on the game in a largely toothless attacking display.
Manager David Moyes brought on Said Benrahma and new signing Gianluca Scamacca just before the hour mark in an attempt to change West Ham's fortunes but Haaland doubled City's lead minutes after and the visitors comfortably saw out the win.
United suffer loss
New manager Erik ten Hag saw the depth of the crisis at Manchester United when his side fell to a 2-1 Premier League defeat by Brighton & Hove Albion at Old Trafford on Sunday, with German Pascal Gross scoring twice.
United fans' hopes that the off-season would mark a turning point have faded, with the club failing to make major moves yet in the transfer market and there was a grim familiarity to the club's opening match.
The former Ajax coach witnessed a performance that was every bit as disjointed as those produced under his predecessors Ralf Rangnick and Ole Gunnar Solskjaer last season.
The sense that this was a continuation of last year's decline began before kick-off where there were yet more loud and angry protests against United's owners, the American Glazer family, under the South Stand
If that felt familiar, then the sight of Scott McTominay and Fred in midfield as United laboured against Graham Potter's superbly drilled side was verging on deja vu.
United had been shambolic in their 4-0 loss at Brighton in May and, even with debuts for defender Lisandro Martinez and midfielder Christian Eriksen, little felt new or changed about the performance.
Brighton took the lead on the half-hour with Leandro Trossard finding former United forward Danny Welbeck who squared the ball to the back post for Gross to slot home.
Nine minutes later, Gross doubled the lead, with his sixth career goal against United, after David De Gea had poorly pushed out a Solly March drive right into the path of the German who again made no mistake.
United went in at the break to the sound of booing from their own supporters -- once a rare occurrence but increasingly part of the experience at Old Trafford.
Ten Hag introduced Cristiano Ronaldo in the 53rd minute and the Portugal forward, who is reported to want to leave the club, provided the spark for United's attempted comeback.
The home side gave themselves a foothold in the 68th minute when a goalmouth scramble ended with Alexis Mac Allister turning the ball into his own net but Brighton held on for a second straight win against United and their first ever at Old Trafford.