There was to be no repeat of the 8-0 success against the Black Cats last season, as Vito Mannone produced fine saves from Dušan Tadić and Oriol Romeu to keep Saints at bay.
The visitors had chances of their own, with Fabio Borini going close on three separate occasions, before a foul on the Sunderland winger from José Fonte saw the Saints skipper sent off with ten minutes to play.
Sam Allardyce's side took full advantage, with substitute Jermain Defoe firing home from close range five minutes from time.
But Saints showed tremendous character to fight back and earn a share of the spoils as Virgil van Dijk slammed home a cross from Tadić.
On the back of defeats to Chelsea and AFC Bournemouth, coupled with injuries to Shane Long and Charlie Austin, Koeman made five changes for the visit of the Black Cats.
Cuco Martina, Jordy Clasie, Steven Davis, Tadić and Graziano Pellè all came into the side, as Koeman reverted to a 4-2-3-1 formation, while 18-year-old Olufela Olomola was named among the substitutes.
After shipping eight on their last visit here – conceding three own-goals in the process – the Black Cats could have done without Wahbi Khazri’s frustration getting the better of him early on. The winger was relieved to see Ryan Bertrand’s free-kick fly narrowly over the bar.
More poor defending from Allardyce’s side presented Pellè with an opportunity moments later, but the Italian striker snatched at his shot and the ball went harmlessly wide.
With 20 minutes on the clock last season, Sunderland were two-nil down, but they were very much in this game and almost took the lead through Borini.
The winger raced onto a pass from Dame N’Doye, but saw his low strike deflected just wide of the near post by van Dijk.
With 26 minutes gone, Saints produced the best move of the match up to that point and almost took the lead. Pellè headed Mané’s clipped pass down for Tadić, but the Serbian’s effort was pushed away by Mannone.
Both sides were creating chances, and after van Dijk had seen a near-post header saved, Jack Rodwell volleyed wide at the other end from Patrick van Aanholt’s cross.
Black Cats goalkeeper Mannone had a torrid day at St Mary’s last season, but he was enjoying a much better afternoon this time around. The former Arsenal stopper did superbly to deny Romeu from close range five minutes before the break.
The visitors began the second half brightly, with Borini twice going close before the hour mark. The first effort was a volley that flew just over the top, before Fraser Forster was alert to beat away his low effort from a tight angle.
A double substitution from Koeman saw Saints lift the tempo, with Bertrand having a shot well blocked after a goalmouth scramble and Pellè also being denied by some last-ditch defending.
Borini was the man most likely to win it for Sunderland, and it was from a foul on him that Fonte received his marching orders after a last-man tackle.
From the resultant free-kick, Forster did superbly to push away van Aanholt’s whipped effort and keep Saints level.
Forster could do nothing about Defoe's goal though, as the striker showed composure from close range to curl the ball into the far corner from Lamine Koné's pass.
Tadić, Juanmi and Martina all went close for Saints in the closing stages, before van Dijk fired home to salvage a point for Koeman's side.
Southampton: Fraser Forster, Cuco Martina, José Fonte (c), Virgil van Dijk, Ryan Bertrand, Oriol Romeu, Jordy Clasie (Juanmi 65), Sadio Mané (Maya Yoshida 82), Steven Davis (James Ward-Prowse 65), Dušan Tadić, Graziano Pellè.
Unused substitutes: Maarten Stekelenburg (GK), Cédric, Harrison Reed, Olufela Olomola.
Goal: Van Dijk (90)
Booked: Bertrand (8), Van Dijk (31)
Sent Off: Fonte (80)
Sunderland AFC: Vito Mannone, DeAndre Yedlin, Lamine Koné, Younés Kaboul (c), Patrick van Aanholt, Jan Kirchhoff (John O'Shea 90), Yann M’Vila, Jack Rodwell, Fabio Borini, Dame N’Doye (Jermain Defoe 59), Wahbi Khazri (Sebastian Larsson 76).
Unused substitutes: Jordan Pickford (GK), Billy Jones, John O’Shea, Ola Toivonen, Mikaël Mandron.
Booked: Khazri (11)
Goal: Defoe (85)
Referee: Neil Swarbrick