Arsène Wenger was keeping his cards close to his chest. He had just been asked whether this Chelsea side is the most vulnerable in the Roman Abramovich era, giving him the perfect opportunity to indulge in a spot of mind games, but he refused to bite, choosing to put the poker face on instead. "I will answer that question on Tuesday," he said, by which time Arsenal hope to have secured the victory they need over Chelsea to return to the top of the league.

Yet that will be no mean feat given Chelsea's psychological hold over Arsenal in recent years, not to mention the fact that Wenger is yet to find a way of getting the better of José Mourinho, losing five and drawing four of their nine matches. Wenger says this match is not about him versus Mourinho, and believes there is no need for him to try to outwit the master schemer by altering his strategy in order to succeed at the 10th time of asking, at the Emirates on Monday night, but it is a statistic that is impossible to ignore.

"Sometimes they have equalised in the last minute at Chelsea and that's not down to a gameplan," Wenger said. "That just reflects the strengths of the teams. I must say for a while Chelsea were stronger than us. You do not have to accept it but it was the reality."

Reality did bite for Arsenal. Since Mourinho arrived at Stamford Bridge for his first spell in 2004, they have won four of their 22 matches in all competitions against Chelsea. Their rivalry has been based on a clash of philosophies, Arsenal's brilliant but doomed fragility at odds with Chelsea's win-at-all-costs attitude. More often than not, it has been a case of men against boys, Chelsea's giants towering over Arsenal and ruthlessly taking advantage of their lapses in concentration. Arsenal won plaudits, Chelsea won trophies.

Arsenal, though, sense that this is their time, not least because Didier Drogba, so often their tormentor in the past, is no longer around to batter a defence that is likely to be missing the injured Laurent Koscielny. Although they come into this match having lost 6-3 at Manchester City, they have felt like a different side this season, more mature and less likely to crumble at the first sign of trouble. Arsenal work harder as a unit and have developed a resilience that allows them to win without playing well.

In the past, Arsenal have been viewed as a soft touch but the addition of Mathieu Flamini has added steel to their midfield, providing the platform for Aaron Ramsey, Santi Cazorla, Jack Wilshere and Mesut Özil to shine. Where once they were easy to bully into submission, now Arsenal will be confident of imposing their passing game on a Chelsea midfield which appears ill-equipped to stop them from bending the game to their will.

This is not a classic Mourinho team. His options in midfield – Michael Essien, Frank Lampard, Mikel John Obi and Ramires – are underwhelming, lacking the power to dominate teams and the creativity to control matches, and failing to protect a creaking defence. Chelsea, knocked out of the League Cup by Sunderland last week, seem to have lost the ability to grind. When Mourinho first won the title with Chelsea in 2005 they conceded 15 goals and recorded 11 victories of 1-0. They have already conceded 18 this season, including 10 in their past five matches.

The game has changed, though. The top sides are less defensive than they were eight years ago and there is a greater emphasis on attacking. "The offensive potential is very big and the structure of the teams is more offensive," Wenger said.

Perhaps Mourinho is still adapting, seemingly caught halfway between constructing a defensively responsible team and delivering the attractive style that Abramovich craves. The Portuguese has the players to pull off the latter but has rarely appeared comfortable with the idea of letting the likes of Eden Hazard and Juan Mata off the leash.

Yet it would be ridiculous to write off Chelsea. For all the noises they have made about this being a season of transition– and it is doubtful whether Mourinho knows the meaning of the word – they have won their past three matches against Arsenal and on each of their past two trips to the Emirates.

Victory on Monday night will lift them up to second, behind Liverpool on goal difference, and leave Arsenal in fourth place.

While Wenger might have kept his thoughts to himself, he will know his team cannot be so reluctant to express themselves.