Key Points

Manchester United were swept aside by the League Two outfit Grimsby Town during a chastening opening 45 minutes, as goals from Charles Vernam and Tyrell Warren saw the Mariners race into a two-goal lead.

Bryan Mbeumo halved the deficit with his first United goal, before Harry Maguire levelled to send the game to spot-kicks, as per a press release on the Manchester United official website..

Matheus Cunha had the opportunity to send the Reds through after Clarke Oduor missed, but the Brazilian was denied by Christy Pym, and a marathon sudden-death period ensued.

Fifteen consecutive penalties hit the back of the net, but Mbeumo's second attempt from 12 yards rebounded back off the crossbar to leave the Reds reeling in the rain.

Ruben Amorim rang the changes for the game in north-east Lincolnshire, with only three players retaining their starting berth after Sunday's draw at Fulham.

A sold-out crowd savoured the first competitive clash between the sides since 1948 and the Mariners were predictably up for the occasion as they harried United's backline with their energetic pressing.

Cameron Gardner saw his header saved by Andre Onana, but the Cameroon international - making his first start of the season - could do little to prevent Grimsby's shock opener when it came midway through the half.

Darragh Burns' curling cross found Vernam unmarked at the far post, and the winger showed great composure to take the ball down and force his shot underneath our no.24. The Reds looked rattled and were relieved to hear referee Tony Harrington's whistle blow after Gardner used his arm in the act of bundling home, but the Mariners were soon two goals to the good.

Onana could not connect when trying to punch Vernam's centre clear, and Warren - once a United Academy player - was able to walk the ball into an empty net.

As the half ticked towards its conclusion, United began to have more of the ball in dangerous areas and, after Pym easily smothered speculative efforts by Amad and Benjamin Sesko, the Mariners' keeper pulled out a more impressive stop from Sesko to maintain the advantage going into the break..

Amorim introduced Matthijs de Ligt, Bruno Fernandes and Mbeumo at the interval, in an attempt to shake his side out of their stupor.

As the rain lashed down at Blundell Park, United had Ayden Heaven to thank for keeping the deficit at two, when the young defender somehow diverted Burns' goalbound shot behind with his shoulder.

Amad curled wide after Sesko had been denied by a stretching Mariners defender, with United playing more on the front foot.

Heaven headed over from Mbeumo's free-kick in steadily worsening conditions, and Gardner was unlucky to see a potential third goal ruled out for offside, despite appearing to be level on the television replays.

Pym did well to regain the loose ball when halting a Fernandes sighter from distance and De Ligt - in a rare position as United's furthest man forward - found the stand behind the goal with his shot as the clock ticked towards 70 minutes and frustrations continued to grow.

Mbeumo lifted the gloom a touch when he cut inside and found the bottom corner to get off the mark, setting up a barnstorming final quarter of an hour, the press release added.

The magnificent Pym somehow swatted clear under pressure from Maguire but could do nothing to prevent our totemic centre-back from nodding in the equaliser at the far post.

Onana looked to be the hero in the subsequent shootout, when he tipped Oduor's kick on to the crossbar, but Pym saved well from Cunha and from there it was a procession of precise penalties.

Both goalkeepers scored and the order had reverted to the original first set of takers, but someone has to miss eventually and it was Mbeumo who would be the unlucky player.

- ANI