Manchester United fell to a jaw-dropping, error-ridden 3-2 defeat at home to Galatasaray as Erik ten Hag’s side saw their start to the season go from bad to worse in an embarrassing Champions League collapse.

Having lost their Group A opener at Bayern Munich and fallen to a fourth defeat in seven Premier League matches on Saturday, the Red Devils reached a new low on a wet Tuesday night at Old Trafford.

Rasmus Hojlund scored a superb second after his opener was cancelled out by Galatasaray’s grinning former United forward Wilfried Zaha, only for Ten Hag’s men to spectacularly unravel.

Kerem Akturkoglu equalised and summer signing Andre Onana’s atrocious pass out straight to Dries Mertens led to a poor Casemiro recovery challenge that saw the Brazil midfielder sent off and a penalty awarded.

The goalkeeper – guilty of a costly gaffe in Munich – was relieved to see Mauro Icardi strike the spot-kick wide, but the striker swiftly made amends as United fell to a third Old Trafford loss of the campaign.

United lie bottom of Group A after two fixtures having failed to “get back on track” as Ten Hag demanded in his programme notes.

Galatasaray had never won in England before and were on the back foot in the early stages, although that early intent did not translate into a clear-cut chance until the 17th minute.

Marcus Rashford raced on to a Casemiro ball and crossed from the right for Hojlund to head home from close range under pressure – the summer signing’s first Old Trafford goal.

United looked to quickly extend their lead but soon their target became regaining an advantage.

Davinson Sanchez sent a hopeful ball from the back in the direction of Zaha, who backed into Diogo Dalot, battled with him and hit an acrobatic attempt that deflected in off the full-back.

The ex-United forward cupped his ears in front of the infuriated home faithful.

Casemiro saw a shot deflect wide and Mason Mount’s six-yard strike was blocked, before then looking to the heavens after his stoppage-time attempt was blocked by team-mate Hannibal Mejbri.

United returned from the break strongly and should have quickly gone back ahead.

After Zaha went down in the box claiming a penalty against Dalot, the hosts broke and half-time introduction Christian Eriksen put Rashford behind.

The forward burst forwards at pace and drew goalkeeper Fernando Muslera before squaring to Fernandes, only for Sacha Boey to beat the skipper to the undercooked pass.

Mount saw an audacious attempt tipped over from the resulting corner and Old Trafford erupted in the 59th minute as they found the net in front of the Stretford End.

Hojlund stood with his arms outstretched in celebration after coolly turning away from his man to score, only to find out he had strayed offside.

Galatasaray were now under siege. Rashford, Mount and Fernandes had attempts before the Red Devils roared again in the 67th minute.

Hojlund collected a loose pass at the halfway line and never gave up, showing strength, power and purpose before lifting over Muslera.

It was a fantastic moment that quickly became a footnote in a chastening night.

Akturkoglu had bent just wide after Onana flapped at a cross and made no mistake with his next opportunity. Quick build-up play ended with substitute Baris Alper Yilmaz passing to him to score after a calming first touch.

Matters quickly worsened for United. Onana’s awful pass out from the back under limited pressure was straight to Mertens, whose was brought down in the box by Casemiro.

The Brazil international was shown a red card and Icardi stepped up to the resulting spot-kick, only to fire his penalty just wide to the delight of the Old Trafford faithful.

Substitute Alejandro Garnacho wriggled through as United looked to retake the lead again, only to be caught cold at the other end.

Former Tottenham defender Sanchez headed back a clearance from Sofyan Amrabat, who inadvertently played Icardi onside and the Argentina strike ran through to lift coolly over Onana in the 81st minute.

Boey and Icardi had further chances, while Antony returned and Anthony Martial had a shot saved before time was called on a humiliating loss.