Despite being dominant in possession throughout the match, Chelsea could not secure all three points against a Southampton side who managed to avoid a sixth consecutive Premier League defeat.
Thomas Tuchel's side held the ball for most of the first half, but it was the hosts who took the lead when Nathan Redmond's defence-splitting ball found Takumi Minamino. The Liverpool loanee was able to calmly slot past Edouard Mendy with the outside of his boot in Saints' first shot of the match.
In fact, Chelsea's only way past Ralph Hassenhuttl's side was from the spot. Danny Ings rashly brought Mason Mount down in his own penalty area and referee Anthony Taylor pointed straight to the spot. Mount picked himself up and fired past Alex McCarthy to put the Blues on level terms.
Despite Chelsea's continued dominance of the ball, they couldn't quite find a way past McCarthy again. Southampton almost snatched all three points when a looping header from Jannik Vestergaard left Mendy rooted to the spot as it hit the crossbar. Callum Hudson-Odoi suffered the ignominy of coming on at half-time then being subbed again for Hakim Ziyech, as Tuchel tried to force a winner.
It wasn't to be for Chelsea on the day, though, as they dropped two crucial points in the race for the top four.
With their goals, Takumi Minamino and Mason Mount both scored seven points overall and Nathan Redmond notched five with his assist on the day.
Following Minamino's loan move and his increasing involvement in Premier League matches, his availability at £6.0m on the official Fantasy Premier League game may be tempting for your free transfer this week.
Anyone who transferred Danny Ings out of their squad will have felt vindicated - Ings was the fourth-most transferred out player between game weeks - as the striker failed to score a goal and conceded the penalty for Mount to equalise.
From the managers
Thomas Tuchel told BT Sport: "We had all the chances and all possibilities to take the win, it would have been deserved, sometimes in football you concede one chance and they score.
"It is always a big week so it is mixed feelings at the moment, it will not be easier to score against Atletico."
Ralph Hassenhuttl with BBC Sport: "A very good point after the last weeks, we deserved more in the last weeks than we got, it was hard for us to play football, we did it one time when we scored and we worked on this during the week. We did what we can do, they pushed us to the limits and the point was the limit today.
"Takumi Minamino does surprising things with the ball, he is physically not the strongest but the intention is there. After the equaliser we kept going so from 65 minutes onwards I felt we could take something from the game.
"The results have not shown what we have played in the last few weeks, now we finally have 30 points and can keep going."
For Chelsea, attention will turn to the Champions League last 16 and one of the toughest tests around as they prepare to face runaway La Liga leaders Atletico Madrid on Tuesday night.
Diego Simeone's side are having an incredible season and will be looking to add European success alongside their push for the Spanish title.
For Southampton, they'll also be in action on Tuesday as they take on the unpredictable and entertaining Leeds United side taking the Premier League by storm.
After a disappointing defeat against Wolves on Friday night, Marcelo Bielsa's men will be out to put that result right. For Hassenhuttl's men, however, they'll be aiming to build on a dogged performance and well-earned point from this lunchtime fixture.
This result will have eased the pressure on Ralph Hasenhuttl and he is now 25/1 with Paddy Power to be the next Premier League manager to leave. Should that happen, Alan Pardew is already a 4/1 shot to replace him.
This draw dented Chelsea's top-four chances, with Thomas Tuchel's side now a shorter price to finish outside the top four (8/11) than to finish inside it (10/11).