Arsene Wenger believes that their title challenge hinges on their game against Chelsea next week at Stamford Bridge.
The Frenchman will lead the Gunners onto the field in what will be his 1000th game in charge of the north London club.
The 64-year-old has won three Premier League trophies with the Gunners and is looking for his fourth success after nine years without a trophy. Their 1-0 win over Tottenham at White Hart Lane has opened up the title race yet again after Chelsea lost to Aston Villa at Villa park on Saturday.
The Gunners took a different route to how their supporters are accustomed to, digging the game out amid a barrage of attacking threat from the home side.
However, Arsenal stuck to their task and rode on the back of a wonder strike from Tomas Rosicky in the 1st minute and defended doggedly with Per Mertesacker and Laurent Koscielny refusing their arch rivals any space through the middle.
A win at Stamford Bridge, Mourinho's first ever in charge of Chelsea at home, will take the Gunners one point within Chelsea, having played a game less.
"It gets us a bit closer to Chelsea and makes the game next week even more interesting. We are now back to four points, we have a game in hand and we have played two away games on the trot because Swansea was postponed so we have five games at home. We'll see, it makes the next game a very big one," Wenger told www.arsenal.com.
"The next game will have a vital importance. I believe as well we came out of three games, Everton, Bayern and today where mentally every time you have to be absolutely focused. That's where I think our defenders have done extremely well because there is no ordinary moment in a game like that and they managed to keep their focus up completely for 90 minutes in every single game," he concluded.