Arsenal kept their second clean sheet of the Premier League season before the international break.
And if they are to continue to make an impact at the top of the table, they are going to need to keep teams out at the back.
Unai Emery's side have enjoyed a good start to the campaign so far, sitting in third place after eight games.
But there are underlying issues that need to be fixed.
The Gunners have conceded 11 goals already this season, more all but three teams in the top half of the table, with expected goals against up at 13.41, according to Wyscout.
Similarly, at the other end, Arsenal have scored 13 goals, compared to the 9.83 they should have netted and that all boils down to an expected points tally of 9.2, which would see them fourth bottom in the Premier League.
As if these stats were not damning enough, there is another which makes for difficult reading for Arsenal supporters.
The defence was a cause for concern for the Gunners last season, with David Luiz and Kieran Tierney brought in during the summer transfer window to help solve such issues.
However, while Tierney has not been able to make an impact in the league as yet, as a result of the injury he came from Celtic with, Luiz has been heavily involved.
But his involvement has not necessarily been wholly useful.
Arsenal have had 545 defensive duels so far this season, averaging 63.29 per game.
But they have only been successful in 58.2% of those duels, which is the second worst in the Premier League, with only second bottom Norwich having a worse success rate.
It is a statistic that needs to change as the Gunners head to Sheffield United for their next match on Monday, October 21, if they are to maintain their challenge at the top of the table.
