The 2019/20 Premier League was pretty much wrapped up by December.
Liverpool had roared to a huge lead at the top of the table. Their unfathomable form, combined with everyone else in the country faltering, created perhaps the most boring title race of all time; we all knew Liverpool were going to win it, it was just a case of when they won it.
27 games into the season, and Liverpool hadn't lost a game. They had barely even looked like losing. The 18-point gap to second-placed Manchester City was a fitting reward for that dominance, and their lead was surely only going to grow when they travelled to meet Watford in gameweek 28.
Watford were 19th at the time, having won just five games all season at that point. They had scored 27 goals in 27 games and were in a relegation battle for a reason. This was probably one of the safest bets imaginable.
90 minutes later, the entire world was speechless.
It's hard to put into words just how surprising it was to see Watford win this game. A nervy, undeserved 1-0 victory would have been enough of a shock, but Nigel Pearson's side went out there, neutralised the soon-to-be champions and picked up an emphatic 3-0 victory.
The Hornets were led by the inspired Ismaila Sarr, who opened the scoring in the 54th minute when he capitalised on some sloppy Liverpool defending to poke home from close range. At that point, Liverpool were still favourites. This was just a setback.
Six minutes later, when he lobbed Alisson and sprinted to the corner to celebrate his second goal, the mood had changed. Watford were actually going to do the unthinkable and beat a team widely accepted to be among the greatest in Premier League history.
Troy Deeney's late strike, which was set up by Sarr, capped off one of the most memorable nights in recent memory.
It was no 'Here's Hogg, Deeeeneeeey ' moment for Watford, but it wasn't far off.
For such a memorable victory, it didn't end up doing much for Watford. They were still relegated when all was said and done and have spent 2020/21 scrapping for a spot back in the top flight. However, it did take a massive toll on Liverpool.
While the Reds roared to a deserved league title, this result blew away their veil of immortality. If Watford could win 3-0, why could better teams not do the same?
As we entered the 2020/21 season, we saw more teams decide to have a go at Liverpool. Realising that damage limitation was not going to work, the plan was to try and out-play Jurgen Klopp's men, and it started to work.
Leeds only narrowly lost 3-2 on the opening day of the season, less than a month before Aston Villa put seven past a Liverpool side which was nearly at full strength. That was obviously an anomaly, but it was an emphatic example of what could happen if you didn't bow down to the Reds' superiority.
There's no denying that Liverpool have been hampered by injuries to the likes of Virgil van Dijk and Joe Gomez for the majority of this season, but the indomitable aura around Liverpool started to dissipate while both were still fit, and that's largely because of Watford's heroic victory.
It's also worth mentioning what this game did to Sarr. The Senegal international went from a high-potential youngster to a potential gem, quickly earning £40m links to the likes of Liverpool and Manchester United. He was given a platform upon which to impress, and he did not disappoint.
Had the COVID-19 outbreak not crippled football's finances, Sarr may well have been straight back in the top flight, strutting his stuff for one of the game's biggest names.