Although I also agree with everyone who says that Chelsea managed to win that match because of luck. But the most important thing is that Chelsea managed to get 3 points for that match. It doesn't matter if it's luck or not. The most important thing is that this luck is also based on the hard work that has been done by the Chelsea squad. But the real problem Chelsea currently has is regarding attack effectiveness. Because actually Chelsea can always make pretty good attacks. But they always fail to solve it.
And this is what makes Chelsea always fail to win.
First of all, they had a winning and shown some signals for their improvement, not only from this winning but from other matches in this season. Chelsea are actually improving and they slowly end their crisis that started in the past season.
Above all, they have yet become as strong as they used to be so they don't stand at top of Premier League but in a long rebuilding process, it is understandable. Give them time, they can improve more, it is my belief about future of Chelsea. A next season will give us better view on Chelsea as this season will still be a transitional season for them. A next season, they must aim at top four and it is like their big target and must achieve it at all cost.