made two key mistakes as let a two-goal lead slip twice in a frantic 3-3 draw at on Wednesday night.
The result means that United’s hopes of reaching the last 16 of the hangs by a thread, with the Red Devils now required to beat Bayern Munich in their final Group A match on December 12 and needing Galatasaray and Copenhagen to draw.
Alejandro Garnacho opened the scoring for Erik ten Hag’s side before Bruno Fernandes silenced the home crowd with an absolute thunderbolt from 25 to 30 yards out.
Ex-Chelsea star Hakim Ziyech scored a free-kick from 20 to 25 yards to pull one back for the Turkish club as Onana made an error and Scott McTominay scored his first-ever Champions League goal in the second half to put United back in control.
Galatasaray refused to give up, though, and another Onana blunder saw Ziyech register his second goal of the evening before Kerem Akturkoglu levelled it up with less than 20 minutes of normal time remaining.
United got off to a flying start and took the lead after just 11 minutes as Garnacho, , finished off an impressive attacking move with a splendid finish, firing into the roof of the net after being set up by Fernandes.
Onana was then forced into a top save to keep out Dries Mertens’ header from a corner and Harry Maguire blocked a goal-bound follow-up from Abdulkerim Bardakci before VAR checked for a possible penalty over a McTominay handball but no spot-kick was given.
Fernandes followed up his assist with a spectacular goal to hand United a 2-0 lead, unleashing an unstoppable effort from 25 to 30 yards out which swerved and dipped before finding the top corner, leaving Fernando Muslera with no chance of saving it.
That silenced the intense home crowd but they were back up on their feet and roaring on the half-hour mark as Ziyech scored a free-kick from 20 to 25 yards out, which went through United’s wall and Onana should have done better after gambling by taking a step to his left, leaving him unable to recover.
The Turkish side pushed for an equaliser before half-time and had the ball in the back of the net after 43 minutes as Mauro Icardi slotted past Onana, but he was narrowly judged to be offside as United held onto their lead at the break.
Galatasaray kept the pressure on as the game restarted with Kaan Ayhan finding himself free at the front post but he was only able to fire his effort into the side netting after a cross from the right side.
The hosts were made to pay for their missed chances as McTominay produced a great finish at the front post having been picked out by Aaron Wan-Bissaka’s low cross after a fine counter-attack, which put the Red Devils back in control.
Just after the hour mark, Onana made another key error to allow Galatasaray back into the game, with the United goalkeeper flapping at the ball from a Ziyech free-kick, letting it go underneath his arm and over the line.
Galatasaray then made it 3-3 on 71 minutes as substitute Akturkoglu took a perfect first touch under pressure and fired his shot past Onana as United blew a two-goal lead for the second time in the match.
Big chances came and went for both sides as they pushed for a winner with McTominay’s low-driven shot going wide of the post, Facundo Pellistri shooting over the bar, Wilfried Zaha opening up space and firing straight at Onana while Fernandes hit the post with five minutes left.
Anthony Martial wasted a key chance with two minutes remaining and Muslera pulled off a big save to stop Pellistri as the game ended in an epic 3-3 draw.
