“We have a neighbour, and sometimes neighbours are noisy, but you can’t do anything about them,” said Sir Alex Ferguson in 2009, when Manchester United were champions of England and fought their squabbles with Europe’s elite, not the blue-shirted big mouths next door.

Fourteen years on, Manchester City are the greatest team in world football and, if that was not enough, their Champions League triumph on Saturday brought a deafening end to their red rival’s claim to be the only English club to have won the coveted treble.

Manchester City have not so much raised the volume as kicked down the fence and raided their neighbour’s trophy cabinet. And in a victory parade interrupted by bursts of thunder, lightning and torrential rain, it was their turn to celebrate.

“Mr Ferguson will be delighted because he will sleep well tonight if he’s around here,” said Gerard Visco, 85, shouting to make himself heard against a cacophony of hooters and fireworks.

A lifelong City fan, Visco cheered the club’s latest champions alongside his son, Dino, 51, and his grandchildren Jessica, 21, and Daniel, 17. “I was here for the ‘68 side [who won the league championship] so I’ve at least seen some success,” he said. “They haven’t seen us lose yet,” he added, pointing to his grandchildren, “and my son hadn’t seen us win for 50 years!”

Cracks of lightning illuminated a sky that turned from blue to grey and back again as the smell of pyrotechnics filled the air and thousands of fans lined the streets.

Erling Haaland, the club’s 22-year-old Norwegian talisman, sent the rain-soaked crowd into raptures as he appeared shirtless and grinning while holding one of the club’s three major trophies. The latest and most prestigious, City’s first ever Champions League, came after an unexpectedly tense 1-0 victory over Inter Milan in Istanbul on Saturday.

Only 20 years ago Manchester City were slugging it out with the likes of Walsall, Rotherham and Wimbledon in the second-tier of English football (the latter club no longer exists). Then came the takeover by Abu Dhabi’s Sheikh Mansour in September 2008, transforming Manchester City into the world’s richest club and beginning a new era of football that is largely dominated by state-backed owners and sovereign wealth funds. The only geopolitics of interest to City fans on Monday, however, was limited to getting one over on their Mancunian rivals.

Jessica Visco, who works in a primary school, hailed the “fantastic” turnaround. “I’m probably in the last generation of children who were bullied in primary school for supporting City,” she said. In assembly that morning children at the school where Visco works were asked if they watched the Champions League final on Saturday. “Over half the hands shot up,” she said. “We’ve taken over, a lot.”

The Champions League triumph was the crowning moment for a celebration that started three weeks ago when City won the Premier League – their seventh in 12 years – followed by an FA Cup victory over (who else?) Manchester United last Saturday.

“This means the world – I’m absolutely buzzing,” said Barry Dean, 73, draped in a huge blue flag. “I’ve been waiting 55 years for this since my first game – against Leeds – when I felt the hairs on the back of my neck stand up and that was me.”

Dean, known in his pub as Barry the Blue, spots a Manchester United shirt over the street and throws a good-natured jibe their way. “Manchester is blue!” grins his daughter, Tina Craig, 54. “The city’s been blue for the last five years,” said Dean. “The bragging rights are ours. Beating them in the FA Cup as well – that’s the pinnacle.”

So idolised are this team that there are calls for statues to be built outside the Etihad stadium. If anyone is to be immortalised in bronze – as Ferguson is at Old Trafford – then it is surely City’s manager, Pep Guardiola, who smoked a cigar as he waved at fans on Monday night.

Guardiola has won 12 major trophies since he took over in 2016 – accounting for 45% of all the major silverware won in the club’s 143-year history. This glittering season may be over, but many believe party may have only just begun – for the neighbours in blue shirts, at least.