1 Giroud struggling to be the big man for the big occasion

It is easy to lament that Olivier Giroud is no Robin van Persie, the man he replaced at Arsenal and a striker whose instincts are well enough known to home fans to have caused great concern when he pinched the ball from Mikel Arteta in the opening moments and homed in on goal. But his shot was uncharacteristically weak, and later, when a delicately worked effort was tipped on to the crossbar, it demonstrated that it does not always go to plan even for the highest-profile forwards.

The sight of Giroud looking agonised as he squanders chances in games against the Premier League's elite has become worryingly familiar for Arsenal, though. Since his goal beat Tottenham on 1 September, he has not scored in the league in seven subsequent matches against the top handful of Chelsea, Manchester City, Liverpool (twice), Everton and United (twice).

2 Back to basics for David Moyes

United looked something they have not been in a while – hard to beat. If a safety-first approach was required to stop some of the self-destruction which has bedevilled them this season, that proved effective. An emphasis on solidity made it difficult for Arsenal to gain attacking momentum. A strong foundation from which to launch counterattacks underpinned United's performance. It almost worked when Van Persie combined with Wayne Rooney, only for Wojciech Szczesny to tip the Dutchman's header on to the frame of the goal.

3 Özil and Mata struggling to find their true roles

Playmakers are under pressure to make the difference. For Juan Mata the situation is complicated by the fact he is not spending much time at the centre of the action. The Spaniard was posted on the left, with Van Persie and Rooney roaming in the area where Mata is inclined to find those pockets of space to affect the game. Again he was tidy, but he was not well placed to conduct the United gameplan. Mesut Özil, burdened with being in the spotlight after a flaky performance in Saturday's 5-1 defeat by Liverpool at Anfield, at times moved the ball with refined dexterity. This was a more promising performance from him. But how he must pine for a pacy runner or two to capitalise on his peripheral vision. Arsenal need to speed up somehow (not easy without Theo Walcott and Aaron Ramsey) to make the most of him.

4 Two teams needing a result were too cautious to bare their teeth

For teams who have either suffered a major setback or are in indifferent form, avoiding any more pain is a powerful incentive against taking risks. Although Arsène Wenger had used the word "respond" like a mantra in the pre-match build-up, stressing how much his team needed to get the anxiety of the Anfield humiliation out of their system, they still started tentatively and found it hard going to raise their game sufficiently to overpower United. It was as if Arsenal's engine was straining as it clambered up a hill in third gear. They wanted to go faster but could not quite manage it. United were happy to be resilient – "compact" as David Moyes put it, with some satisfaction – but they were also short of the creativity to cause serious damage.

5 Arsenal's big-game troubles leave them frustrated again

There were similarities here to the last time Arsenal needed to recover from a dreadful defeat. They played Chelsea at home immediately after the embarrassment of losing 6-3 at Manchester City, and although a goalless draw against José Mourinho's side was hardly the end of the world, it felt like an opportunity lost. Here Arsenal were urged on desperately to break down United in the second half but they lacked the penetration and ruthlessness. Santi Cazorla led the charge late on to turn one acceptable point into three thrilling ones. But David de Gea demonstrated fine reflexes to handle anything and everything. Another home clean sheet for Arsenal (that's 11 from 12 games at the Emirates) but their lack of a deadly finisher is costing them.