Marcus Rashford impressed for Manchester United on a night when their defence had a shocker in their unacceptable collapse against Porto in the Europa League.
Erik ten Hag made four changes for the trip to Portugal with Casemiro, Christian Eriksen, Amad Diallo and Rasmus Hojlund selected ahead of Kobbie Mainoo, Manuel Ugarte, Alejandro Garnacho and Joshua Zirkzee.
Porto started the match on top but it was United who took the lead when Rashford ran at goal from the left wing and squeezed a low effort beyond Diogo Costa.
They soon had a second when Rashford played through Rasmus Hojlund, who also fired an effort past Costa at the near-post, in what was a night to forget for the Porto goalkeeper.
It looked like United were well on course for a comfortable win, only for them to collapse in catastrophic circumstances in European competition under Ten Hag once again.
Pepe capitalised on poor defending from Lisandro Martinez to head his side back into the match and seven minutes later they had an equaliser when Samu Omorodion beat Matthijs de Ligt to a cross and headed into the back of the net.
Things then went from bad to worse when star performer Rashford was withdrawn at half-time to be replaced by Alejandro Garnacho and Samu struck shortly after the restart to give his side the lead for the first time in the match.
United looked lost for ideas as they tried to find a way back in the game but they rarely troubled the shaky Costa in an atrocious second-half performance. Any hopes of getting back into the match faded with ten minutes left when club captain Bruno Fernandes was sent off for a second yellow card following a high boot.
However, there was to be even more late drama when substitute Harry Maguire headed in from a corner to rescue a point for the 10-men and ease the immediate pressure on manager Ten Hag ahead of a trip to face Aston Villa in the Premier League this weekend.
Here is how we rated the United players in the match:
1. Andre Onana - 7
Made a superb stop seconds before Pepe bundled the ball into the United net. Little he could do about the other two strikes that beat him and denied Samu a hat-trick. Another game in which it would have been much worse without him. | Manchester United via Getty Images Photo: Manchester United via Getty Images
2. Matthijs de Ligt - 2
He was terrorised by Samu all night and at fault for both of his goals. The ultimate humiliation when he was replaced by another centre-back with his side trailing in the match. | AFP via Getty Images Photo: AFP via Getty Images
3. Lisandro Martinez - 2
He switched off inexplicably for Pepe's goal and was all over the place for both of Samu's. Nowhere near the levels of last season and couldn't complain about being hooked. | AFP via Getty Images Photo: AFP via Getty Images
4. Noussair Mazraoui - 3
Made an important block early on but struggled as the match progressed. Beaten too easily for the first goal and poor positioning all night. | Manchester United via Getty Images Photo: Manchester United via Getty Images