Diego Costa’s second-half brace guided Chelsea to a 4-2 win over Southampton on Tuesday evening. 

Eden Hazard and Gary Cahill got The Blues’ other two goals, both of which came during the first period.

Ex-Chelsea players Oriol Romeu and Ryan Bertrand scored The Saints’ two strikes, with each coming either side of half-time.

The win moved The Blues temporarily seven points clear of London rivals Tottenham Hotspur at the top of the Premier League table.

However, Spurs defeated Crystal Palace 1-0 on Wednesday night to reduce the deficit back down to four points.

Chelsea club captain John Terry announced last week that he will be departing the club that he has played for since he was 14 at the end of the season.

Terry was a second-half substitute in The Blues’ victory and his brief cameo role was the first time that the defender who has won 14 major honours with the club has played in the Premier League since the start of November.

Shoot! looks at five things we learned from Tuesday’s goal fest at Stamford Bridge…

The gap increased

Following their FA Cup semi-final triumph last Saturday, Thee Blues were able to pick up their second 4-2 victory in the space of three days.

This time last week, Chelsea were still coming to terms with a 2-0 defeat to Manchester United, as well as having their lead at the top of the table cut to just four points.

The Blues are back to their best following recent victories against The Saints and Tottenham, with just five league games remaining.

Saints’ struggles

The defeat for Southampton means that they have only picked up seven out of a possible 18 points in their last six matches.

They’ve only beaten Crystal Palace and West Brom in their last six, having drawn against South Coast rivals AFC Bournemouth and losing their other three matches against Tottenham, Manchester City and Chelsea.

Claude Puel’s side have been struggling to pick up victories recently, and their tough recent fixtures have contributed to this.

Unfortunately for Southampton, it is not going to get much easier in terms of their tricky run-in to the end of the season.

Their last six games include four home games against Hull City, Arsenal, Manchester United and Stoke City, as well as two away games against Liverpool and Middlesbrough.

Realistically, Puel’s side don’t have a lot to play for and the majority of their upcoming fixtures come against sides that are going to be desperate for wins.

Southampton fans should not be too disheartened as they still have a chance of beating some of the best sides in country before the season ends next month.

Back with a brace

Diego Costa returned to his scoring ways on Tuesday night, having not scored in his previous seven games for the Blues.

Costa’s first goal was a fantastic header from a smartly taken corner. That was his 50th Premier League goal, making him only the seventh Chelsea player to have reached that feat.

Soon after the goal, Costa’s confidence shot back up, the home fans that were singing his name encouraged him to go and get his second of the match.

He combined with Eden Hazard and Pedro in a move which saw him both a start and finish a superb Chelsea move.

The 28-year-old Spaniard was named man of the match after grabbing two goals and providing the first goal, when he set up Belgian team-mate Hazard.

Costa has regained form at the best possible time as Chelsea go into their last six games in all competitions in the hunt for the league and FA Cup double.

Ryan’s return

Tuesday’s six-goal thriller saw both Ryan Bertrand and Oriol Romeu return to their former home at Stamford Bridge.

The duo were both part of the 2012 Chelsea side that won the UEFA Champions League in Munich.

Bertrand made his European debut in the final, where he started at left midfield and played 73 minutes before being replaced by Frenchman Florent Malouda.

Tuesday’s match proved that the ex-Chelsea duo were not forgotten by the South West London faithful.

They may have got The Saints’ two goals last night, but Chelsea fans were not angered to see their ex-players score, with Chelsea fans even celebrating Bertrand’s header and singing “There’s only one Ryan Bertrand”.

Problems at the back

Chelsea may have comfortably won last night, but there is still a sign of defensive frailty in the side.

The Blues have not kept a clean sheet in the league since January’s 2-0 victory against Hull City.

Returning skipper Gary Cahill chipped in with a vital goal for Chelsea on Tuesday, but the fact that they are conceding is still slightly alarming.

However, Chelsea have recently found that the best way to win is just to focus on how many they score rather than how many they concede.

If they can become more solid at the back, then they stand a better chance of winning the double next month, but if it is going to affect their goalscoring ability, then they may want to leave defensive problems as an improvement point for the summer.