Manchester United squeezed through to the Carabao Cup fourth round, 5-3 on penalties, Daniel James confidently dispatching the decisive kick on a night when Rochdale gave Ole Gunnar Solskjær’s men an almighty scare.

Yet the result should not mask the latest worrying display, one that followed Saturday’s defeat at West Ham, as they were taken to spot-kicks by a 16-year-old right-back named Luke Matheson. He will long remember his 76th-minute equaliser and sprint to celebrate in front of the Rochdale fans he had sent into ecstasy.

Manchester United beat Rochdale on pens, Oxford 4-0 West Ham: Carabao Cup – live! Read more

Matheson, an A-level student, will be 17 next week but it was United’s own 17-year-old, Mason Greenwood, whose earlier strike appeared to have won the tie. United then drew Chelsea at Stamford Bridge in the next round and the manager said: “If you want to win it you have to beat the best.”

Solskjær had retained only Aaron Wan-Bissaka and Andreas Pereira from the West Ham loss. The headline inclusion was Axel Tuanzebe who, at 21, captained United in only a 10th appearance. He was the youngest to do so since a 20-year-old Norman Whiteside in 1985. This was despite Paul Pogba’s first start for close to a month because of injury.

Brian Barry-Murphy’s side are 17th in League One, six points above the relegation zone after nine games, yet reached the break on level terms.

Of particular interest was how Greenwood would perform in his first game as United’s No 9 – and he impressed. He would have had a first clear chance if Pogba had turned a far-post header to him. Moments later, he was put in along the left by the same player but his control faltered.

United seemed to be moving closer to the breakthrough: Greenwood crossed the ball in from the right, yet Pogba’s header was a particularly woeful miss. Possession was largely United’s but they lacked the class and composure to make it count.

Oxford United humiliate West Ham in shock Carabao Cup thrashing Read more

There was then a real scare for the United defence: it could do nothing as Ollie Rathbone – once of United – found Callum Camps and suddenly Wan-Bissaka had to clear off the line.

This had the packed away end delirious and the home support wondering what, precisely, their team was doing. Rochdale could start to believe the upset was on.

Greenwood was United’s brightest player, as he continued to pop up in and around Robert Sánchez’s goal.

The sign of United’s desperate times came on the hour when Solskjær replaced the toothless Tahith Chong for James, whose impact was instant, laying off a pass to Greenwood whose shot forced Sánchez to concede a corner.

Then United had the breakthrough and Brandon Williams, on his debut aged 19, was instrumental. He found Pereira, who relayed the ball to Jesse Lingard: Greenwood took over, and it was 1-0. Yet now came the twist as Matheson raced in from the right and buried a finish past Sergio Romero and penalties beckoned.

Rathbone finished disappointed but proud. “It was amazing We were expecting to get drummed here. We did really well,” he said. Solskjær added: “You know we’re better in penalty shootouts than in proper games.” He was joking yet some fans may be worried that such a jest is now true of their team.