The two titans of English football came head to head in what turned out to be a thoroughly one-sided encounter. Almost everything went right for Arsene Wenger and his men, and almost everything went wrong for Louis Van Gaal’s.

Arsenal flew out of the blocks and scored three scintillating goals in the first 20 minutes, with Alexis Sanchez virtually finishing the tie with a bullet from outside the box. It was clear the two teams came to the battle with different mindsets; Arsenal came fully loaded with fully automatic submachine guns ready to blast their way to goal, while United came trying to reason with them. We know how that works when facing a loaded gun. Here are some takeaways from yesterday’s encounter.

Theo Walcott is adjusting to the striker role

There was a reason The Professor took a gamble and did not go all out for a £30 million centre forward: he believed in Theo Walcott. Walcott has taken time to learn the different intricacies of playing as a centre forward, but from yesterday’s evidence, one can say he is making that role his own.

Not only was his movement fantastic, but Walcott worked hard off the ball. At one point in the game, Walcott chased back into midfield, dispossessed Bastian Schweinsteiger, got back on his feet, and continued the attack.

This optimal mix of deadly movement and off the ball graft is exactly what Arsenal fans want to see. They must pray then, that this sort of intensity from the #14 continues, and that it was not just a reactionary performance to the Gunners’ midweek disaster.

Rooney lets the game pass by him, yet again.

Wayne Rooney was poor. But that has become the norm for him now. Let’s just put it this way: If Rooney stepped out of the pitch for 10 minutes to have a beer, no one would have noticed, such was the level of his contribution.

Playing as a #10, one of his main duties was to keep an eye on Santi Cazorla, the main orchestrator, but he failed to do his job, prompting Van Gaal to shift him to the left in the second half. Fans may recall that a similar failure occurred against Real Madrid when Sir Alex Ferguson asked him to be vigilant on the right-hand side. After witnessing him fail to do his defensive duties in the first leg, Ferguson dropped him for the second.

Some fans are reluctant to put the blame entirely on Rooney, and rightly so, the entire team played badly. However, the issue of Rooney is such a huge one in a wider context. He certainly was not solely responsible by any means, however, his mere presence has become a hindrance to the tactical flexibility, fluidity and functioning of Manchester United.

Years have gone by when he has been ‘sacrificed’ for the team, and the moments he has been given central prominence, his extent of contribution has not justified the elevation which has accompanied it.

Schneiderlin’s presence missed

The midfield selected by Van Gaal was interesting. In a game where the commanding of space was vital, many people would have had Morgan Schneiderlin as the first name on the team sheet. Schneiderlin would have been able to deal with the pace of Arsenal’s midfield.However, Van Gaal opted to trust Schweinsteiger with that task, with less than favorable results.

Schweinsteiger in particular, unable to impose himself on Arsenal’s midfield, winning only 11% of his tackles. Francis Coquelin on the other hand won 71% of his tackles.

The midfield duo were too slow and failed to deny space for Mesut Ozil to operate in, which proved to be costly.

Alexis Sanchez bearing the torch to see Arsenal through

Matteo Darmian has been solid this season for Manchester United, but Alexis Sanchez tormented him to such a great extent that Louis Van Gaal thought it best to take him off at half time.

Sanchez has displayed a resilience that only a few players possess in world football. After starting the season poorly, by his standards, he has picked up his form and silenced his doubters in fantastic fashion. With two shots and two goals to tell, Sanchez ran riot against a hapless Manchester United defense.

After Robin Van Persie’s departure in 2012, Arsenal have not had that talismanic figure who could guide them through bad spots. If it isn’t evident already, Sanchez is that new man, providing vital contributions in almost everything Arsenal do. His two goals were taken with skill and panache and his overall contributions were nothing short of brilliant.