Southampton started with the high-tempo pressing that has characterised Mauricio Pocchettino's short reign so far, with Chelsea struggling to get into things from the off.
Chelsea had rotated plenty of players with their game against Manchester United in the FA Cup looming, and it showed as they put together a largely disjointed performance from a lineup that would have given the Saints a huge boost before a ball had been kicked.
It was no surprise, then, to see the Saints take advantage and put themselves in front by opening the scoring. Jay Rodriguez got the goal, taking advantage of a fine pass from Steven Davis, who showed why he had played his way back in the starting eleven. The well-weighted through ball found Rodriguez's run perfectly, and his finish was unerring and precise to leave Petr Cech with no chance.
What followed was a typical moment for Chelsea and for John Terry. Against the run of play, the Blues equalised from a set-piece, John Terry overpowering Jos Hooiveld to power a header into the net from a corner and put his side back in the game.
Yet in a game that was swinging one way to the other, Chelsea were not level for long. It was another set-piece that brought the next goal, although it was a moment of real class, Rickie Lambert firing a glorious 30-yard free-kick into the top corner of the net that left Cech without a prayer.
The second half should've seen Chelsea improve, but the Blues continued to put in a stuttering performance in 45 minutes of football that proved extremely scrappy, with the ball mostly bogged down in midfield and no real chances at either end. Indeed, the visitors were not really into the game until, predictably, Southampton's pressing dropped off as the game got towards the last 30 minutes.
Yet with the Saints turning to defending deep, Chelsea could not make their increased possession count. They did come close twice, with Victor Moses' mishit shot forcing Kelvin Davis to tip the ball onto the crossbar, and Frank Lampard's late free-kick whizzing wide of the post, but it was a defeat that was all too predictable for Chelsea - if they fail against Manchester United, there will be serious questions asked.