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.
Against Southampton they had to win because they are one of the weakest teams in the Premier League and Chelsea have a very tough fight with City and Nottingham for the top 4, so it is very important for them to get points and after two defeats against Aston Villa and Brighton they needed this win. Then there is a match against Leicester which they also have to win, and then two tough games against Arsenal and Tottenham.
Chelsea's tough fixture against Southampton was very important and they managed to win the match without any surprises. They won the match comfortably by four goals. Southampton is very close to relegation. They showed no presence against Chelsea and will be relegated from the Premier League. Chelsea will have tough matches in their remaining matches. They must win these matches if they want to stay in the top four.