It was all or nothing for Arsenal.
A thoroughly depressing season had left them on course for their biggest disappointment in two decades, the Premier League set for a top four that excluded the Gunners for the first time since 1996.
Last week’s derby humiliation at the hand of fierce rivals Tottenham Hotspur had all but sealed their fate. Down in sixth place, six points off Champions League qualification with just five games remaining, the jig was up.
Anything other than victory over Manchester United on Sunday would have been the final nail in the coffin. The Gunners had won just one of their last eleven Premier League matches versus Man Utd – against whom under-fire Arsenal coach Arsene Wenger had his lowest win rate (29%).
In the opposite dugout sat Jose Mourinho, who’d never lost a Premier League game to Arsenal, Wenger having gone 12 matches without getting the better of the Portuguese.
Moreover, Mourinho’s side arrived at the Emirates unbeaten in 25 successive Premier League matches (W13 D12) – a club record within a single top-flight season.
Arsenal had to end the hoodoo – and there was air of inevitably about the fact that former Man Utd forward Danny Welbeck stepped up to break the hex, heading the all-important second goal in a famous 2-0 win.
Welbeck’s performance earned him an impressive 90/100 on the Goal Pressure Index, presented by Sure and powered by Opta data, which provides the first ever system to measure and rate a team and player’s performance under pressure.
The Goal Pressure Index uses more than 750,000 data points as well as factors including league position, point in the season and the opposition to calculate a rating out of 100 for every Premier League player every week.
Earlier this season Mourinho was openly critical of his club’s recent transfer policy, stating his belief that mistakes were made prior to his arrival, and he held up the decision to offload Welbeck to illustrate his point.
Welbeck has now scored in each of his last three appearances versus Manchester United for Arsenal in all competitions.
The warning signs were there. The England international saw a shot excellently blocked early on before only a flying challenge from Chris Smalling prevented him opening the scoring after half an hour.
Arsenal got a stroke of fortune ten minutes into the second half when Granit Xhaka’s speculative long-range shot took a huge deflection off Ander Herrera and lopped over Man Utd goalkeeper David De Gea.
But there was nothing lucky about their second, arriving three minutes later to put the game beyond Mourinho’s side.
Alex Oxlade-Chamberlain whipped in a vicious cross that saw Welbeck leap to power his header in off the bar. And there was no restrained celebration from the England international.
"I grew up there and it's a special place in my life, but once we get on that pitch it's just business at the end of the day," he told Sky Sports. "It's for the team. When you score, you've got to be happy. It's only normal."
Wenger beating Mourinho wasn’t normal. But then neither is a Premier League table which omits Arsenal from its top four.
Six points behind fourth-placed Manchester City, with just one game in hand, Arsenal still face an uphill task. But now, thanks to Welbeck, thanks to the only man whom it could ever be, they have a fighting chance.