With an FA Cup quarterfinal replay against Manchester United following just two days later—while also taking Thursday's Europa League clash with Rubin Kazan into consideration—something had to give for the Blues, and this fixture was it.
Of the starting XI, there were just five who could be considered vital, established first-team players. Peter Cech, Frank Lampard, John Terry, John Mikel Obi and Branislav Ivanovic have long been part of the fabric at Stamford Bridge, but beyond them on Saturday, Chelsea lacked any real authority.
Fernando Torres' struggles are well-documented, while Victor Moses, Ryan Bertrand, Cesar Azpilicueta and Marko Marin are not yet the stars they have the potential to be.
The sight of Oscar's endeavors as part of the attacking three behind the striker pretty much summed up the afternoon, as the Blues battled for supremacy but without any real conviction.
In some ways, this outing on the south coast reflected a cup game more than anything. As the underdog, Saints had sniffed out weaknesses in their weakened opponents and, with a passionate home crowd behind them, did just enough to come out on top, 2-1.
It was a fine win for the Premier League strugglers, yet as much as it outlined their desire to remain in the top flight, the victory was also a stark reminder of Chelsea's shortcomings this term.
Benitez has come in for some criticism following his team selection, and as manager, the Spaniard will shoulder his share of blame for a defeat many will consider a major upset.
It's not as simple as that, though, and shouldn't be considered as such, either. In the closing stages of the season, Chelsea find themselves in a difficult position.
Do Chelsea have what it takes to finish the season in the top four with silverware?
On one hand, the Blues have it all to play for, fighting on all three fronts in the Premier League, FA Cup and Europa League. But while it may be exciting, it's equally unnerving as the fixture congestion their cup campaigns bring could very well mean they end the season empty-handed. No top-four spot, no FA Cup and no Europa League trophy.
Benitez is trying to achieve this with a threadbare squad. While the Blues look strong in numbers, they lack the experience to capitalize on the situation in which they find themselves.
It comes back to this notion of transition, and while their squad list may read like a who's who of fantasy football, the reality is it's all come a little too early for them.
Beyond the usual suspects at Stamford Bridge, Chelsea are dealing with players expected to be the heroes of the next generation, but nonetheless, players who have to prove themselves.
Saturday outlined that much and while they will learn from defeat, this season could very well have come too early for them.