Arsenal have looked defensively susceptible throughout the season and have conceded goals they should not have.
Although the Gunners have suffered with injury problems, the players who have featured have not always delivered.
On Saturday, Arsenal received a huge defensive boost as Laurent Koscielny started the game against West Bromwich Albion.
The France international central defender had missed seven matches with an Achilles tendon injury before being named on the bench for Arsenal's Champions League encounter against Borussia Dortmund last week.
The 29-year-old then started the Premier League clash against West Brom at The Hawthorns on Saturday and did not look like he had been out at all.
With Koscielny partnering 2014 World Cup winner Per Mertesacker at centre-back, Arsenal looked much more solid and compact.
The former Lorient star is set to start against Southampton at the Emirates Stadium on Wednesday, and Arsenal’s twitter page made it clear just how important he is.
Arsenal FC (@Arsenal) December 2, 2014
Following weeks of inconsistent results, Arsenal appear to have regained some confidence. One suspects that much of that has to do with the return to full fitness of the best centre-back at the club.