Maybe now it should be clearer why Louis van Gaal has been telling anyone who cares to listen they should not be surprised if Manchester United’s rehabilitation takes longer than they would ideally like. He had warned his new club to brace themselves for some difficult moments and here was the hard evidence that a change of manager at Old Trafford is not simply going to wash away the team’s shortcomings.

It was a cloying sense of deja vu attached to the team that finished seventh last season, 22 points off the top and drastically in need of some more dynamism. They were short of ideas, huffing and puffing their way towards a demoralising defeat. There was a startling lack of creativity and if Van Gaal had listened closely he would have made out the mocking chants from the away end, as the visiting fans embarked on the repertoire of songs that formed the soundtrack to David Moyes’s time in the job. New manager, same old story, even if the home crowd would like to trust there is better to come.

Swansea were too streetwise, defending in a pack then breaking on the counterattack and exploiting the mistakes in United’s defence to win through Gylfi Sigurdsson’s 73rd-minute goal, the midfielder making an immediate impact in his second stint with the Welsh team. Sigurdsson, signed back from Tottenham Hotspur in the summer, was also involved when Ki Sung-yueng gave Swansea a first-half lead and it would be unfair on Garry Monk’s team if their performance was largely overlooked amid the scrutiny on their opponents. They never lost their nerve even after Wayne Rooney’s equaliser early in the second half, when United finally looked like they might rediscover some of the old panache.

It turned out to be a deception and Van Gaal, with the disappointment etched on his face, will certainly have learned more about what needs to be put right. Unfortunately for him, it is a considerable list bearing in mind the shortage of pace, the erratic passing of Chris Smalling and Phil Jones and the general lack of flair, as if somewhere along the line this proud club have lost sight of what should be expected in those red shirts. The new manager talked afterwards about seeing players who had allowed nerves to undermine their performances. He sounded startled that they had been afflicted that way.

The sight of Tyler Blackett in the back line and Jesse Lingard starting the match as the right wing-back should also conjure up mixed feelings. Van Gaal likes to remind his audience he was the manager who brought through a 16-year-old Clarence Seedorf and gave a debut to the teenage David Alaba and Thomas Müller, among others, but in United’s case these players were being fast-tracked into the team because of the fragile nature of their squad, exacerbated by a punishing injury list and a lack of signings.

Blackett did, however, acquit himself well and Lingard was unfortunate to be injured after a bright start.

Van Gaal has been working with a 3-4-1-2 system ever since he took the job but here, too, was the proof that too much can be read into positive pre-season results. At half-time, the new manager had seen enough and abandoned everything they had been practising. Ashley Young was moved to left-back in a more orthodox 4-2-3-1 formation, albeit lacking natural full-backs, and briefly there was at least an improvement. Rooney hooked in Jones’s flick-on from a Juan Mata corner and at that stage it was easy to imagine the classic fightback, petals being thrown at Van Gaal’s feet and the sense of a wonderful new beginning.

Back in the real world, Old Trafford is no longer a place where opponents expect to be beaten. “I can guarantee nobody gave us a hope,” Monk said afterwards, praising his team for their togetherness. Swansea played with belief and composure, with Ashley Williams excelling in defence and Sigurdsson dovetailing nicely with Ki and Jonjo Shelvey.

Smalling was caught out by a quickly taken free-kick and Jefferson Montero, one of the visiting substitutes, broke down the left before turning his cross into the penalty area. Wayne Routledge’s shot was mistimed, coming in from the right, but the ball fell kindly for Sigurdsson to side-foot a follow-up effort that struck the goalkeeper, David de Gea, but crept over the line.

United had plenty of the ball as they desperately tried to concoct one of their late moments of drama but their problem all afternoon was that they rarely did enough with it. Too often, the ball was passed around at the back, or sideways through an unimaginative midfield. It was when they had to be more adventurous that they came up badly short. Robin van Persie was badly missed and Javier Hernández was poor enough to be substituted at the interval.

Swansea had the greater pace and penetration and opened the scoring in the 28th minute. Until that stage, they had barely threatened but Ander Herrera did not track Ki’s run closely enough and Wilfried Bony, an oak tree of a striker, did a superb job of getting in the way of Jones, so that his team-mate could pick his spot without anyone closing him down. Nathan Dyer and Sigurdsson had worked the ball to Ki from the right and his left-foot shot found the bottom corner from just outside the penalty area.