Mark Robins is credited with scoring the goal that saved Ferguson from the chop, an FA Cup third-round winner against Nottingham Forest in January 1990.
United went on to lift the trophy, Ferguson's first at the club, the triumph proving the catalyst for the unprecedented success that was to follow.
But Sivebaek can lay claim to the goal that kick-started a quarter of a century of glory under Ferguson, one that has yielded 12 Premier League titles, two European Cups, five FA Cups and three League Cups. It was he who grabbed the only goal of the game against QPR at Old Trafford in November 1986 - Fergie's maiden victory.
"It's special to have scored the goal that gave him his first win at United," said Sivebaek.
"We won a free-kick 20 yards out and I wouldn't normally be anywhere near the ball for that. I wasn't known as a goal-scorer or a dead-ball expert but had been taking some and thought it was worth a shot.
"I was lucky to score but it felt great. There was relief for the gaffer as it was his first victory.
"It was the first of what is now hundreds and hundreds of wins. He has been great and has deserved his 25 years."