Yes, Chelsea team has used their advantage against Southampton and has been able to attack enough and achieve victory. They were very aggressive at the same time, which has inspired their fans by taking advantage of Southampton's weakness. After winning against Southampton, Chelsea has changed their position by collecting 3 points and they are currently in fourth position in the points table. However, since Manchester City has been able to capture the position, of course this season I think there will be a lot of competition between Manchester City and Chelsea, just to qualify for the UCL next season.
Chelsea played very well against Southampton and won game. They were very aggressive and showed Southampton weaknesses, which made their fans very happy. Win helped Chelsea move up to fourth place in standings and get important points. But Manchester City is also trying to finish in top four so competition will get even tougher. It is likely that Chelsea and Manchester City will fight very hard to get spot in the Champions League next season. So let's see who will win in this race.