A frustrating game at a sunny Selhurst Park saw Crystal Palace twice pull themselves back from falling behind to earn themselves a point on a day when both sides could have netted several times more.
The clash was a close-fought affair and both Palace and United players will have left the pitch reflecting on what could have been as each sit in the top three of their respective leagues.
The game opened swiftly, with Levi Lumeka seeing an early effort hit too softly into Kamil Miazek's arms, but it was the visitors who kicked into gear fastest when Ryan Edmondson netted within five minutes at the heart of the Eagles' penalty box with Kun Mihaylov having knocked down to him well.
First-team forward Jordan Ayew was the first looking to react for Palace as he cut well along the left and into United's box, however his cross was intercepted by the opposition defence. The Ghanaian's teammate Sam Woods rose from the resulting corner, though his well-hit header ended up in the empty Selhurst seating.
The 27-year-old Ayew could then almost celebrate bringing Palace level just seconds later only for Miazek to intuitively react and pull off a remarkable save from just five yards following a low Jairo Riedewald drill from the right.
The game settled down after 10 minutes of end-to-end play, however took a sour turn when Woods was forced to leave the field after an uncomfortable fall, bringing his match to an end.
Palace continued to come close to goal, with Riedewald threading through Lumeka with just a little too much pace on the ball.
For Leeds, Izzy Brown kept Palace alert throughout the half, regularly finding smart passes from midfield or encouraging threatening surges towards the Eagles' box. Shortly before the 40th minute, he found Jack Clarke wide in Palace's area, however the No.7's shot was high into the gloves of Lucas Perri.
The pair linked up marvellously again later when Brown rotated on the penalty spot before gifting Clarke a clear chance at goal, however Nikola Tavares defied him from nowhere, hitting the deck and dispossessing the Leeds man emphatically.
A Clarke header was then again held by Perri before the referee blew for half-time.
The second half opened well for Richard Shaw's men, with the returning Luke Dreher netting in the 51st minute after Lumeka drilled a ball across from the left wing into his path. It took just one touch to strike home and pull the Eagles level.
Almost immediately after, Ayew burst through one-on-one only for Miazek to swipe the ball from his boots. The Palace forward came close to atoning for the lost chance when he stepped up to strike a free-kick won by Brandon Pierrick, though his shot flew inches wide of goal having beaten the wall.
At the other end of the pitch, Perri was then called into action when Mihaylov drove a low strike at goal which the Brazilian got down to tip around the post.
From a quick Ayew free-kick, Riedewald then found himself one-on-one with Miazek but took far too long to strike the ball and instead back-heeled into the path of the on-running Ayew, who struck wide of goal from a shallow angle.
The Eagles were made to pay for their squandered efforts when Alfie McCalmont ended up at the tail end of an attacking move which saw him slot past Perri from close range to regain the advantage for the visitors.
It wasn't to last long, though, when substitute Kian Flanagan picked up the ball and, as he does so well, rifled home from the edge of the box with a strong left foot. With just five minutes of time remaining, all was left to play for as the two top-three clubs battled out the last few chances on offer.
The opportunity to grab the winner then fell to Lumeka but, perhaps under the pressure of scoring, he struck wide of goal and the game ultimately wound to a stalemate close.
The chance to reach the play-offs this season has dwindled with this draw, then, and Thursday's game with Watford becomes a crucial end to a season still verging on glory for Palace's Under-23s.
Palace: Perri, Tavares, Mitchell, Woods (D.Boateng 21), Inniss, Riedewald, Pierrick (Daly 82), Dreher (Flanagan 77), McGregor, Lumeka, Ayew.
Subs: Webber, Trialist.
Leeds: Miazek, Davis (Shackleton 45), Struijk, Hosannah, Gotts, McCalmont, Brown (Stevens 45), Bogusz, Mihaylov, Clarke (Odour 45), Edmondson.
Subs: Male, Diaz.