If Chelsea are to sustain their challenge for the Premier League title, they may well point to this performance as one that validated the view Antonio Conte’s revitalised side can last the course.

Built on the foundation of a defence that has been impregnable since Conte reorganised his back-line four-and-a-half matches ago and inspired by a revitalised Eden Hazard, who scored the opening goal, taking his tally to five league goals, one more than he managed in whole of last year’s troubled campaign, this was a convincing victory at the home of a team that came into the game on the back of a run of steadily improving form.

Diego Costa confirmed the win with an outstanding second half effort, struck from outside the area, for his eighth goal in ten league games. While last weekend’s emphatic victory win against Manchester United may have been more eye-catching, but this was equally impressive as Conte’s side served up a display that will have been noted by the three teams who sit one point above them at the head of the table.

Claude Puel’s Southampton side had not lost at home since a very different Chelsea won here eight months ago and came into this game have conceded just two goals in five unbeaten games. That run was ruined when Hazard put the visitors ahead after six minutes and it quickly became clear the home side would struggle to become the first side to break down Chelsea’s three-man central defence since Conte made the switch when his side were trailing 3-0 at half-time at Arsenal 405 minutes of playing time ago.

The case for Chelsea as title contenders is growing in strength but Conte insists, that with the top of the table as congested as it has been in a very long time, judgement on their credentials should be withheld until the second half of the season.

“At this moment, it's not important for us to look at the table,” said the manager. “We are in a good position, but it's not important. It's more important to work very hard and trust the work will improve us.

Hazard was mobbed by his team-mates after striking early on (Getty)

“The only way that we must know now is to continue to work. Not look at the table. But, if you ask me a prediction or an expectation of our championship, now it's very difficult to talk about this.

“It's important to pass many games particularly in the first part of this season. And then you can see if you can stay up there in the title race. It's important to pass the first part of the season. Then, when you start the second part, our ideas will be more clear. We are working a lot. I'm seeing a lot of positive things in the team. We are not looking at the table, but continuing just to work.”

Hazard’s outstanding work in the opening moments of the game set the tone with the winger taking the opportunity to drift inside, exchange passes with the excellent Victor Moses before getting in behind Steve Davis and drilling an angled shot through the legs of Fraser Forster. The Belgian’s contribution did not surprise Puel, who managed Hazard at Lille, and the Southampton manager believes his former player is now back to his best.

Austin and his Southampton team-mates failed to muster many opportunities (Getty)

“He has come back after last season's difficulties, and has come back at a very good level,” said Puel. “He played with this level, so it made it difficult for us. But we could have done better at his goal. But he's a very good player, of course, like Costa.”

Costa should have added a second when he was set free by Nemanja Matic shortly before the interval but Southampton’s threat had been so limited, it never seemed likely the miss would prove costly. However, ten minutes into the second half, the Spain striker made up for his mistake, making space outside the Southampton area and curling a long-range effort beyond Forster.

"Four wins in the league now, four clean sheets – we keep going,” said Gary Cahill, the Chelsea centre-back. "It’s too early in terms of any team talking about winning the league but it’s important to stay near the top. We want to be up and among it. I can’t see anyone running away with it this season."

Teams

Southampton (4-2-3-1): Forster; Martina, Fonte, Van Dijk, Bertrand (McQueen 78); Clasie (Boufal 61), Romeu; Tadic (Hojbjerg 78), Davis, Austin; Redmond.

Subs not used: Taylor, Yoshida, Ward-Prowse, Olomola.

Chelsea (3-4-3): Courtois; Azpilicueta, Luiz, Cahill; Moses (Ivanovic 87), Kante, Matic, Alonso; Pedro (Willian 78), Costa (Batshuayi 88), Hazard.

Subs not used: Begovic, Oscar, Terry, Chalobah.

Referee: M Jones (Cheshire)