To win a match you don't have to dominate it, but you have to take advantage of every opportunity and create as many chances as possible. Chelsea took advantage of their opportunities well despite creating 4 good chances throughout the match. Actually, just 1 goal was enough to make them win the match, but there were still many shortcomings.
This is the fact, even Chelsea since the beginning of the season has been having good ball possession and lots of chances to score But thank God they where able to get a clean sheet and a win.
What is clear is that winning this match against Brighton will help Chelsea's confidence and increase even more. In that match Chelsea's game was really interesting and there were many changes made by Poct, Chelsea not only scored goals and won, but Chelsea did it by playing very differently. Look at the ball possession stats - 40-60 in favor of Brighton.
Usually when Chelsea play they always control the ball, but can't score goals, but that night they played very effectively, especially in the first half. Chelsea actually played relaxedly and let Brighton control the ball. This changed the whole dynamic, as too often Chelsea controlled the game until and on the attack this time they let it go, and they waited for a quick counter-attack.