Maurizio Sarri reinstated Alvaro Morata to the team with Olivier Giroud ruled out, yet the service to the Spaniard was poor as Saints dug deep to hold on for a well-earned point.
A tame first half passed with few flashpoints, though Chelsea did see Willian forced off on the same day the club announced the signing of Christian Pulisic, who will arrive at the end of the season.
The home side had a Morata goal controversially ruled out for offside late in the second half as they failed to win at home for a second successive outing, following on from a shock 1-0 reverse against Leicester City on December 22.
It took Chelsea 33 minutes to craft their first meaningful opportunity, Eden Hazard finding space in the left side of the area and firing an effort which came back off the face of Premier League debutant Angus Gunn.
Willian was forced off after a collision with Maya Yoshida a few moments later, further decreasing Chelsea's depleted forward options.
And while Sarri will no doubt wish Pulisic was available immediately, Willian's replacement Ruben Loftus-Cheek looked lively.
The England international set Morata up for a chance 12 minutes from time only for the former Real Madrid man to shoot straight at Gunn from a tight angle, shortly after he was adjudged to have strayed offside when finding the net.
Chelsea's desperation towards the end resulted in Marcos Alonso going down easily under pressure from Shane Long in the area, but referee Jonathan Moss correctly ignored the protests, allowing Saints to hold on.
22 - Angus Gunn (22y 346d) is the youngest English goalkeeper to start their first Premier League match since Jordan Pickford (21y 315d) on January 16th 2016 (for Sunderland vs Spurs). Saint. pic.twitter.com/TcY0lLajwQ— OptaJoe (@OptaJoe) January 2, 2019
What does it mean? Chelsea need reinforcements
Sarri has made no secret of his desire to sign more players, and Wednesday's match laid that issue bare. With Willian off injured, a glance at their bench showed precious little attacking talent. Hazard cannot be expected to do it all – he needs help in the fight to finish in the top four.
Gunn silences disappointing Chelsea
Sarri's men were far from their best, but when they did manage to test Gunn, the goalkeeper - who has patiently waited for his opportunity since joining from Manchester City - looked completely at ease on his first top-flight start.
Barkley devoid of craft
It was by no means a surprise to see Ross Barkley hauled off just after the hour, as the England international did not offer a great deal of invention in midfield.
Key Opta Facts
- Southampton recorded their first Premier League clean sheet since October. Prior to the stalemate with Chelsea, they had conceded 24 goals in their previous 10 games.
- Chelsea have failed to score in three of their last five Premier League games at Stamford Bridge, as many as in their previous 22 in the competition.
- Southampton have drawn nine Premier League games by a 0-0 scoreline since the start of last season - two more than any other side.
- Angus Gunn (1) has recorded more Premier League clean sheets at Stamford Bridge than his father Bryan (0 in 3 attempts) did in his entire career.
- Cesc Fabregas came on in the second half for the Blues to make his 500th appearance for English club sides in all competitions.
After Saturday's FA Cup visit of Nottingham Forest, Chelsea have an EFL Cup semi-final first leg with Tottenham before returning to Premier League action against Newcastle on January 12. Saints go to Derby in the FA Cup at the weekend, then travel to Leicester City a week later.