I think it's 8 points but since they have one more game than City, that means as long as City wins that extra game, the difference is still 5 points and nothing really changed aside from getting one more game closer to finish line.
Only ten games left. Even if Manchester City win the missing game and decrease point difference to 5, that means Arsenal have to slip in two games and City don't make any mistakes. It doesn't look like both teams make a mistake though. Both teams will play with Liverpool and Chelsea and they play with each other. There is no fixture advantage for any sides. I still believe Arsenal will go until the end and lift that long awaited trophy.
Arsenal's and Manchester City's chances of winning the premier league will be determined by their clash and a few other remaining matches. Although the chances of both teams losing their remaining matches are rare. But in football, anything can happen.
It's a victory for both teams competing against Liverpool and Chelsea. Chelsea and Liverpool are not in their best form to win against Manchester City or Arsenal
If Arsenal finally wins the premier league after many years without a trophy, I will be delighted. The premier league was last won by them in the 2003–2004 season.