Harry Maguire's injury-time equaliser saved Manchester United boss Erik ten Hag from another damaging defeat after the Red Devils blew a 2-0 lead in a 3-3 draw at Porto in the Uefa Europa League on Thursday.

Marcus Rashford and Rasmus Hojlund had given the visitors a dream start with two goals inside the first 20 minutes.

But a double from Samu Omorodion, after Pepe brought Porto back into the game, had the English giants heading for defeat.

United then had captain Bruno Fernandes sent off for the second consecutive game, but the 10 men salvaged a point when Maguire headed in a corner.

Ten Hag's men have now begun their Europa League campaign with two draws after being held at home by FC Twente last week to sit 21st in the 36-team table.

And the manner of their capitulation after a fast start will do little to ease the pressure on their manager ahead of Sunday's daunting Premier League trip to Aston Villa.

"We started the game very good, we dominated, scored two good goals but then we lost control," said Ten Hag. "The middle part (of the match) was no good."

The former Ajax boss has defiantly defended his record after winning the League Cup and FA Cup in his first two seasons in charge at Old Trafford – ending United's six-year trophy drought in the process.

And Ten Hag insisted he should be judged at the end of the season.

"We will get there, don't judge us in this moment," he added.

"Judge us in the end of the season. We will improve, we have two seasons where we achieved finals," he said. "Just wait – we will develop and progress this team."

Ten Hag could not have wished for a better start, even if Porto were architects of their own downfall. (AFP)