As Arsenal get ready for their second league game of the season against Manchester City, we take a look at what we learned from their opening day win over Birmingham City last weekend.

1The team is strong when reactive.

As soon as they went down to 10 players, Arsenal took charge of the game. Emma Mitchell came on at left-back and the team went to full attacking mode and were rewarded with two late goals. The women’s team showed some of Arsene Wenger’s fabled “mental strength” and hopefully it will carry on throughout the season.

2Pedro Losa made some big choices in defence

Lining up with a centre back pairing of Josephine Henning and Dominique Janssen, he also selected Jessica Samuelsson at right-back and Heather O’Reilly at left-back

He left five defenders on the bench in Jemma Rose, Louise Quinn, Alex Scott, Emma Mitchell and Taylor Hinds, with only one attacking player alongside them.

Playing HAO at left-back was a huge gamble considering four different defenders could have played in that position. Louise Quinn was introduced for Dominique Janssen making Jemma Rose the de facto fourth choice centre back in that game.

3Putting round pieces in round holes is a risky business

Pedro Losa continues to tinker.

Despite playing the usual 4-3-3 system, there were a couple of players out of position who actually did very well, like Beth Mead. Some, like Heather O’Reilly, who has not yet mastered the art of being a defender, not so much.

It was a baffling move to put O’Reilly in that position, to be honest. Although her inclusion means an extra attacking body in the team, in terms of timing, positioning and defending she has a lot to learn. When you consider how difficult it is to learn the art of defending, it is was a difficult situation to put her into.

Competition for places will be interesting once all the injured players are back. All 21 players will be genuine contenders for a starting 11 place. Pedro Losa will have tough choices to make every game.

4The damage could have been worse

Had Birmingham City been more adventurous and attacking Arsenal might not have got away with all three points.

Ellen White was isolated as a lone striker but still managed to find space for many runs behind the Arsenal defence. She was supported by Andrine Hegerberg in the playmaker role and Emma Follis who was alternating between the wing.

Had Birmingham put another quick forward alongside Ellen White, they would have created a lot more chances as the Arsenal defence was a bit slow overall.

Also, when they went an extra player up, the Blues made the mistake of dropping deeper and deeper and inviting pressure. Those kind of mistakes are unlikely to happen against a team like Chelsea or Manchester City.