It looks like luck because they only won by a narrow score and the goal was scored via a penalty kick after a Fulham player fouled one of Chelsea's players, but actually Chelsea continued to appear to put pressure on the away team but unfortunately, their chances were not able to penetrate Fulham's defense, even their opponents several times made quite good attacks and threatening their goal.
Chelsea was quite grateful because Cole Palmer managed to calmly execute the penalty kick because if he had failed, Chelsea would have gotten another bad result. In the final minutes, they managed to maintain their defense which continued to receive attacks from Fulham who were trying to get 1 point by doing so to equalize the score.
Chelsea's performance was ordinary even though this was their third win in a row and with a performance like that they would still probably lose to any team because their game development was not very good.
If they win all their matches this way and get to the top, nobody will give a damn about how they win as long as they remain at the top. What matter most is they should win their match which they won Fulham. I'm proud to see some adjustments in the table but how long will they go is something we can't say now because they once pull some battle with Manchester City in the same season, that game impressed everyone including that hasn't been a fan but they didn't do well after that, so I don't know what will happen in their subsequent matches.
There is a problem in managerial positions of Chelsea players but more importantly, they need to build a strong foundation of striker, the forward looks dead and the midfield looks weak. Pochettino still has time to make adjustments in necessary places instead those worthless comments he always rush to make when there loss match, always use to "I believe in this project, we just need more time bla bla bla" and the season has pass half way to the second leg.