Manchester City were last night crowned European football champions, completing the treble after their FA Cup and Premier League victories this season.

Many City fans trace the team’s march to glory back to their dramatic win over Gillingham at Wembley in 1999, when they secured promotion to the second tier of English football – then known as Division One – by snatching victory from the Kent side in agonising fashion.

These were different times for City, a former Premier League side whose struggles had seen them relegated to Division Two the previous season. Four days before they faced Gillingham in the play-off final on May 30, their neighbours and rivals Manchester United had just completed the treble under Alex Ferguson, with victory over Barcelona in the Champions League final.

Gillingham faced City in front of 77,000 fans – including Oasis stars Liam and Noel Gallagher – at the old Wembley stadium, with a place in what is now known as the Championship at stake.

For the Gills, under manager Tony Pulis, it offered the possibility of a second promotion in three years – a remarkable achievement just four years after slumping into administration and facing expulsion from the Football League. For City, managed by Joe Royle, it was the chance for a swift return after they found themselves in the third tier for the first time in their history.

With nine minutes to go, the game was on a knife-edge at 0-0. But then a flowing move led to a toe-poked goal by striker Carl Asaba. Little over five minutes later, Asaba’s cheeky back-heel sent his strike partner Robert Taylor clean through. A stunning finish and the Gills were 2-0 up with just three minutes to play.

But as the final minute of the 90 started ticking down, City grabbed one back through Kevin Horlock. In the fifth minute of added-time, as the Gills fans urged the referee to blow the final whistle, City’s Paul Dickov scored a stunning equaliser past Gills goalkeeper Vince Bartram – who had been best man at Dickov’s wedding.

Extra-time gave way to penalties and three missed kicks later, the Gills were defeated and City promoted back to Division One. They would return to the Premier League the following season and became champions for the first time in 2012, going on to win it a further six times, including the last three seasons.

But nearly a quarter of a century later, the Gillingham play-off final remains ‘iconic’ to many City fans as the turning point in their fortunes.

Speaking to The Guardian on the 20th anniversary of the game, Paul Dickov said: “I dread to think what might have happened if we hadn’t have won. If you believe what people were saying, the club would have really struggled. It’s probably just as well we didn’t realise how important it was as it would have put more pressure on us.

“If anything it’s been magnified more by the success. Maybe 10 years ago fans would stop in the street, thank us for the goal in the game and that would be it. Now, the club are dominating football and with the football that they are playing it makes it more iconic and nicer for the fans to think that 20 years ago we were there, 20 years later we’re winning Premier Leagues and breaking all sort of records.”

Speaking about the goal against best friend Bartram, Dickov said: “There is nothing better than getting one over your mate or reminding him of it a few years later.”

Writing in football magazine When Saturday Comes, City fan Ian Farrell claimed: “So much hung on the outcome, much more, in real terms, than on most higher-profile shootouts. Failure would have almost certainly seen Royle sacked and players and club staff let go as the financial crisis deepened. City would have had to accept that they were not slumming it anymore: that this was who they were.

“With City in the Premier League 12 months later, the play-off was viewed as the great turning point.”

Gillingham came through the Manchester City defeat and a year later returned to Wembley, where they celebrated play-off victory over Wigan Athletic.

The Gills came from behind to win with two late goals in extra-time.

Club legend and former manager Andy Hessenthaler, who had been through the heartache of 1999, said: “To have been able to go back to Wembley the year after and then basically turn it around and get promoted was unbelievable. To come back from the heartache of losing to Manchester City takes a lot of character and we showed it.

“We deserved to go up against Man City, it was just the last few minutes that went against us, but we put it right the year after and the way we did it was unbelievable."

The Gills had gone 2-1 down in that play-off final and Hessenthaler admitted that the worst crossed his mind.

Speaking on the 20th anniversary of the Wigan game, he said: “We’re thinking ‘oh no, not again’. But fortunately we dug in, we kept going and kept believing and fortunately for us we popped up with a couple of bits or real quality at the right time to win the game.”

Headed goals from Steve Butler and Andy Thomson won it for the Gills.

Hessenthaler took charge of the Gills for their years in the second tier, following Peter Taylor’s departure for Leicester City. Progressing year on year and ending up 11th in 2003, the highest the club have ever finished in their season.

The Gills are now looking forward to a new era under the ownership of Brad Galinson.