Manchester City underlined the vast gulf in quality between themselves and Manchester United on Sunday as Liverpool showed their support for absent team-mate Luis Diaz, whose parents were kidnapped in Colombia.
Old Trafford paid tribute to late United great Bobby Charlton ahead of kick-off, with supporters unfurling a banner that read: "The finest English footballer the world has ever seen".
But memories of past glories failed to translate onto the pitch, with the home team thoroughly outplayed by the champions, who did not have to get out of second gear in their 3-0 win.
Champions City made most of the early running and were awarded a penalty after VAR spotted a foul on Rodri by Rasmus Hojlund as the ball was crossed into the area from a free-kick.
It was the first spot-kick Manchester City have been awarded at Old Trafford since 1992.
Erling Haaland stepped up to tuck home, his 12th goal of the season in all competitions.
City goalkeeper Ederson saved a Scott McTominay pile-driver before Andre Onana produced heroics at the other end when Haaland appeared certain to head home.
But the Norway forward made no mistake just after the break, thumping home a header from Bernardo Silva's cross.
Phil Foden made it 3-0 with 10 minutes remaining after he was set up by Haaland.
Guardiola said it was one of City's best performances of the campaign.
"I had a feeling that at this part of the season we are playing better than at this point last season," he told the BBC.
"When we come here to Old Trafford we perform well -- last season we lost, this season we won, so good."
United manager Erik ten Hag, whose team have now lost five of their opening 10 league games, refused to comment on the penalty award.
"It hurts a lot," he said. "I think especially because first half the game plan went perfectly. It is only the penalty that changes the game."
- Liverpool tribute -
Earlier, Liverpool swept Nottingham Forest aside by the same scoreline.
Goals from Diogo Jota and Darwin Nunez before the break and Mohamed Salah's second-half effort ensured Jurgen Klopp's side maintain their 100 percent home record in the Premier League this season.
Jota held aloft Diaz's number seven shirt after scoring -- the Colombian did not feature in Liverpool's squad following the kidnapping incident in his home country.
More than 120 soldiers backed by police are combing northern Colombia for the father of Diaz, kidnapped with his wife, who has since been rescued.
The army said in a statement it had set up roadblocks and deployed two motorised platoons, unmanned aircraft, helicopters and a plane with radar in the search for Luis Manuel Diaz.
Liverpool boss Jurgen Klopp said preparation for the game had been "the most difficult I've ever had in my life".
"I don't want to make the game bigger than it was, but definitely, we tried to help Luis with the fight we put in because obviously we want to help and we cannot really help," he said.
Liverpool finished the day fourth in the table, behind leaders Tottenham, Arsenal and City.
High-flying Aston Villa, in fifth spot, won their 12th consecutive home game in the Premier League, beating struggling Luton 3-1.
Unai Emery's side made light work of their opponents, with goals from John McGinn and Moussa Diaby giving them the upper hand before Luton captain Tom Lockyer put through his own net.
Brighton lost further ground after their sparkling start to the season.
The south coast club took a 1-0 lead through Evan Ferguson, but Fulham levelled through midfielder Joao Palhinha.
Dominic Calvert-Lewin scored the only goal of the game as Everton beat West Ham 1-0 to give themselves breathing space above the relegation zone.
jw/mw
