The Whites have now lost their last five FA Cup games, with their last win in the competition coming as far back as January 2017.
It was certainly an afternoon to forget for Marcelo Bielsa's side but after selecting what looked to be a fairly strong starting XI, what went wrong for Leeds United?
• The starting lineup
Before the game, Bielsa's decision to name a mixed but strong starting lineup did not raise too many eyebrows.
Resting the likes of Patrick Bamford, Mateusz Klich, Stuart Dallas, Luke Ayling and Illan Meslier from the matchday squad completely seemed unquestionable after the number of games they have played over the last 12 months.
Gifting starts to current fringe players such as Ian Poveda, Helder Costa, Jamie Shackleton and Pablo Hernandez, mixed with the regulars Rodrigo Moreno, Kalvin Phillips and Liam Cooper left Leeds with what looked like a sufficient combination to get the job done against League Two Crawley.
But Leeds looked far from their usual selves. Even when the Whites have fallen to heavy defeats in the Premier League this season, they have usually posed some sort of threat throughout the game and their dominant, slick style of football has resulted in an enjoyable display.
Leeds managed just two shots on target and only created two 'big' chances all game.
Rodrigo, who started as the number nine, offered very little upfront and winger Costa lacked quality with his final ball. 20-year-old Poveda looked Leeds' brightest spark as he tried to get in behind the Crawley defence several times but barring a shot that was well saved by the goalkeeper, Glenn Morris, his overall efforts resulted in very little threat to the home sides goal.
In midfield, the ever-reliable Hernandez was unusually quiet, Shackleton struggled to find his range, misplacing a number of simple passes, and Pascal Struijk failed to have any impact on the play.
Whilst Leeds did not really pose any threat on the Crawley goal, the Red Devils were also fairly quiet offensively in the first half. Leif Davis, Ezgjan Alioski, Cooper and Phillips defended steadily throughout the first half. The out-of-favour Kiko Casilla seemed to deal with any aerial threat quite well and he made a wonderful save just before half time to deny Reds forward, Tom Nicholls.
• Half-time substitutes
Not many Leeds United fans will ever question a Bielsa decision because, well, his decisions normally work, but bringing off Rodrigo, Struijk and Cooper at half-time was very strange.
At 0-0, Leeds were still in the game and sending the same side out for the second half was what most Leeds fans expected.
It's safe to say it didn't work.
Jack Harrison replaced Rodrigo in the nine position, 18-year-old Jack Jenkins came on for his debut, replacing Struijk, and Cooper swapped with Oliver Casey.
These three substitutions arguably weakened a side that was already offering little.
And from the 45th minute onwards, every Leeds player was off the pace.
Crawley looked the more likely to score, they wanted it more and you could tell. In the 50th minute, their efforts were rewarded after Nicholas Tsaroulla battled well in midfield, twisting and turning, before touching it past the onrushing Phillips and Casey and firing powerfully across Casilla, who possibly could have done better as it found its way into the bottom corner.
It did not get any better for Leeds. Their lack of guile in midfield was exposed and some poor passes allowed Crawley to play in behind Casey before Ashely Nadesan's shot beat Casilla at his near post to make it two.
The nail in the coffin for Leeds came in the 70th minute. A set-piece was not dealt with properly by Leeds and after an initial shot was parried, Jordan Tunnicliffe made no mistake in poking home from 4 yards out.
Bielsa's substitutes were very unorthodox in terms of their timing and the way the game was going. Whilst the substitutes are not solely to blame for the loss, Bielsa has to take responsibility for his choices throughout.
The decision to start with a strong lineup would have been made to try and ensure Leeds won the game. Making changes that did not strengthen the side at half-time then lessened Leeds' chances of winning. Whilst it is bizarre, it is hard not to trust the Argentine after all he has done.
In a fair conclusion, for a change, Bielsa got it wrong.
• Focus on the league now
Although a cup run would have been nice for Leeds, the most important thing this season is that they stay in the Premier League.
Losing to a team three divisions below is not the way Leeds, Bielsa or the fans would have preferred to go out of the FA Cup but many have come to terms with Leeds not doing so well in any cup under Bielsa.
This was not a great day for anybody involved with Leeds but for the players, all they can now do is bounce back in their next game.
The fringe players that felt they didn't produce must go again and keep trying hard.
The result yesterday was only a blip in what has been a great start to the season for Leeds. Now, they must kick on in the second half of the season and focus on winning as many games as possible.
Up next is Brighton at home on Saturday 16 January.