Arsene Wenger believes the hard-fought win at Aston Villa on Monday demonstrated Arsenal's defensive improvement this season.
The Gunners had to sustain late Villa pressure after Christian Benteke's 75th-minute goal but managed to hold firm to secure their fourth league win in a row and return to the top of the Premier League.
Arsenal have not been known for their backs-to-the-wall performances in recent years but Wenger believes that has changed.
"Now we go into a part of the season where every game becomes massive"
"Villa offered us a real British game in the second half and we could deal with that area," he said. "We certainly were not capable of doing that before.
"Of course what you need is stability defensively. We have seen that against Cardiff, we didn't concede and in the end we are always capable of scoring a goal."
Arsenal host Fulham at Emirates Stadium on Saturday afternoon and the Frenchman feels his team are entering a critical period of the campaign.
"We know that one of the targets in the second part of the season is for us to be strong at home and recently we have done that," he said.
"We want to continue that until the end of the season because we have some big games. One of them is [Saturday] because Fulham for us is always a derby. It is of course a very important game because now we go into a part of the season where every game becomes massive."