Ole Gunnar Solskjaer believes Peter Schmeichel’s dramatic save from Dennis Bergkamp’s penalty in the 1999 FA Cup semi-final replay between Manchester United and Arsenal altered the course of history.
United - who were down to ten men after Roy Keane's sending off - looked dead and buried in injury time of the iconic game at Villa Park on April 14, 1999 when Phil Neville fouled Ray Parlour in the penalty area with the game poised at 1-1.
Dutch star Bergkamp, who had already cancelled out David Beckham's opening goal, stepped up to take the penalty which would have sent the Gunners to Wembley - but could not beat Schmeichel.
United went on to win, thanks to Ryan Giggs' dramatic winner, and subsequently won the treble.
And Solskjaer believes Schmeichel's save was crucial in ensuring United won the Premier League title - they finished one point ahead of Arsenal - as well as the FA Cup.
"The semi-final in 1999 is such an important game," Solskjaer said, speaking ahead of United's FA Cup game against Arsenal on Friday night.
"When Peter saved that penalty from Denis Bergkamp, that gave us the advantage and we went on to win the treble.
"If Bergkamp had scored they would have won the double. This just how small the margins are.
"That is the standout for me. I was substituted so I watched Giggsy's goal from the sideline. What a goal that was!"
The rivalry between Sir Alex Ferguson's United and Arsene Wenger's Arsenal defined almost a decade of English football.
For seven seasons after Wenger arrived in 1997, the two sides dominated the Premier League, with Arsenal winning three titles and United four, before the arrival of Jose Mourinho in 2004 broke that stranglehold.
Solskjaer recalls: "When I played, they were our closest rivals. They won the double, we won the treble.
"The games against them were just fantastic. We had a great team, but they had a very good team as well.
"The famous back four and David Seaman - I think I scored once against Seaman, just once. They were great games that you looked forward to.
"I think I won two semi-finals against them, and we lost 2-0 at home once. There were some tackles flying in between the two teams."
The rivalry has diminished somewhat in recent years as other dominant teams have emerged in English football.
Both clubs are still in the process of establishing their new identities following the departures of Wenger and Ferguson.
United, in particular, have struggled in that regard with David Moyes, Louis van Gaal and Jose Mourinho all sacked by the club.
Solskjaer has taken over an interim basis and is pressing his case to get the role permanently with seven wins from his opening seven games, but at this stage, the future is uncertain for both him and the club.
Arsenal turned to Unai Emery to replace Wenger and the results over the first half of the season have been largely positive.
Solskjaer believes the Gunners have chosen wisely.
"Obviously, Arsene and the gaffer, they were the two longest-serving managers in my era and they were fantastic the two of them, like an institution in their clubs," Solskjaer said.
"But Unai, when he had Sevilla, they beat Molde in the European Cup so I have had the pleasure of meeting him before and I think they have made a very good signing there.
"He is tactically very good, [with] high energy. I don't know what team he is going to play. He has got loads of different tactics to come up with."