Manchester United's defeat to Arsenal on Wednesday night was a reminder that it is easier and quicker to improve a team's defensive structure than to change the way they attack. For large parts of the game, United looked secure in open play against one of the more offensive teams in the league, but when they had the ball in the opposition half, they carried almost no threat of their own.

In four matches under Ruben Amorim, United's style has clearly changed. His 3-4-3 system and the tweaks he has made have stopped games from becoming the end-to-end basketball-style contests they often descended into under Erik ten Hag. United aren't giving up as many opportunities and can exert greater control on proceedings.

Even in the first half, there were times when Amorim's team held on to possession and had the shape to manipulate the ball, keeping it across the back three, looking for Diogo Dalot and Tyrell Malacia as they hugged their touchlines and trying to find space between the lines. The problem was that when possession reached the final third, they often ran out of ideas.

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Speaking after the first defeat of his tenure, Amorim admitted after the game that he just hasn't had the time to really improve his team's attacking play. While he wants more aggression and bravery in attack, it is going to be a process.

“We didn’t have the time," he said. "We work a lot on building up. You can see the structure, you can see the idea, you can see the bounce when the centre-backs go into the midfielders.

"But then in the last part or the last third, you can see that we need to improve, be more aggressive, more ideas. But that part is more difficult to improve without a lot of training."

The problem is the 39-year-old has joined the club at the worst possible time for someone who improves teams via work on the training ground. He had his entire squad together for two sessions at the end of the international break and is now on a relentless run of two game weeks.

The next gap of any reasonable length between games doesn't come until after Christmas, with United in action on the night of Monday, December 30 and then Sunday, January 5. The following midweek could contain a Carabao Cup semi-final of United knock out Tottenham in two weeks. If it does, there will be a game every midweek until February, and that schedule only allows for, at most, a couple of full-on training sessions in a week.

February could finally offer Amorim and his new coaching staff the chance to really dig into the details with a prolonged spell of training groundwork at Carrington, but again, it depends on their success. United will have two midweek breaks in February if they finish in the top eight of the Europa League league phase.

They currently lie 12th with trips to Plzen and Bucharest to come and a home tie with Rangers. Two wins and a draw should probably be enough to reach the top eight, and the reward of avoiding a two-legged play-off is substantial for a new head coach.

Amorim has improved United in his four games in charge, but he knows with the schedule as it is, the increments of advancement will be small. As this season progresses and the fixture list finally begins to ease, we will start to see a braver, more cohesive attack emerge. But it might take until February before the signs of progress are really visible.