A lot had changed for both clubs in the months since the Saints stunned the reigning champions at Stamford bridge earlier in the season, prompting a now infamous seven minute post-match rant from Jose Mourinho.
Southampton found a degree of consistency in the new year and going into the game Fraser Forster hadn't conceded a goal since returning from injury in January. On the other side, Diego Costa was enjoying the kind of excellent scoring run that he couldn't have imagined under Mourinho.
It meant that something, somewhere, had to give. Ultimately, it was the former.
If Hiddink has given Chelsea anything since taking over in December, it's defensive stability. But that was severely lacking when Long put the home side into the lead late in the first half. Baba Rahman's lazy header let the Irishman in and with Thibaut Courtois rushing out, a composed, exquisite dink saw the ball ripple the far corner of the net.
Prior to that moment, even half chances had been few and far between for either side in what were rather windy conditions on the south coast.
Southampton looked dangerous from set-pieces - a Long header in the opening 10 minutes might have given Ronald Koeman's side the lead earlier - while Chelsea appeared to lack energy and intent. Willian, as he has been so often this season, was a rare bright spark in an otherwise disappointing first half for the Blues.
Chelsea were just generally lacking attacking quality. After the break, Hazard, who is still looking for his first Premier League goal of the season, fired high and wide after cutting in from the right.
John Obi Mikel appeared to lose his bearings in the six-yard box and somehow managed to head a glorious chance wide, while Costa later couldn't control a left footed volley enough to the hit the target and ask a serious question of Forster.
When the equalising goal came there was more than an element of fortune about it. Fabregas virtually passed the ball into the far corner, with Forster unsighted as Hazard threatened to get to the ball in front of him.
To add insult to injury for Southampton, only moments earlier Charlie Austin was denied a possible penalty as Gary Cahill made a meal at his attempt at a covering tackle.
The goal served to give Chelsea more confidence and the 89th minute winner from Ivanovic almost had a sense of inevitability about it. As Willian swung in a corner the Serbian rose high above a sluggish Virgil van Dijk and powered a header low at goal. Forster got a hand to the ball, but couldn't keep it out.