Wilfried Gnonto fired the Whites ahead after just 55 seconds and defender Raphael Varane turned into his own goal early in the second half as Leeds seemed on course for a first league win at Old Trafford since February 1981.
But Erik ten Hag's United rallied in the 2nd half with a Marcus Rashford header followed by substitute Sancho’s first goal since September in a thrilling 2-2 draw.
Illan Meslier superbly stopped Varane scoring a winner at the end of a rip-roaring tussle that adds excitement ahead of Sunday’s return fixture at a Elland Road.
If it is a one-game reign, then what a game. Michael Skubala may return to the shadows, to the world of Under-21 management, but only after a heady taste of the limelight.
Leeds ended the host's run of 13 successive home victories.
For an hour, they were on course for a first league victory at Old Trafford in Skubala’s lifetime. But, with and without Jesse Marsch, Leeds have a tendency to lose leads and Manchester United have the resolve to mount a response.
Leeds were marching on together without Marsch, contributing to a classic, playing with a verve and a dynamism that may have been a reaction to the manager’s sacking. But, by the end, they only have two wins in 18 league games.
Yet it was about a newcomer, a returning hero and the great constant in every Manchester United storyline at the moment. When Leeds could envision ending a wait that dates back to back to 1981, Rashford scored his inevitable goal.
He has 20 for a season that has almost four months left to run. Yet a comeback was completed by a player on his own journey back: Sancho's first goal since September came on his longest outing since October. Half an hour as a substitute offered a reminder of his quality.