Yoan Gouffran's goal gave the Magpies the advantage but Mauricio Pochettino's half-time changes improved the visitors, who have now not won in their last five games
Jay Rodriguez's seventh goal in all competitions this season cancelled out a first-half opener from Yoan Gouffran, the Frenchman's fourth strike in his last four home matches.
Both sides had chances to win it in a very open second half, with Loic Remy guilty of spurning a glorious one-on-one opportunity late on.
|VIEW FROM ST JAMES'S PARK
|By Harry Slavin
A tale of two halves in the North East as Newcastle failed to build on strong first-half performance to allow the Saints to leave St James's Park with a point.
Alan Pardew's men were quick out of the blocks in the opening period and could have been home and dry had Loic Remy not passed up a great opportunity to continue his fine goalscoring form.
Two changes from Mauricio Pochettino at the break turned the game on its head, though, and the introduction of Adam Lallana proved inspired as the England international set about tormenting Pardew's side.
A draw will sting the Geordies but, in the end, they were perhaps fortunate to get away with anything.
Newcastle manager Alan Pardew, facing his former club, was without the suspended Yohan Cabaye, who picked up his fifth booking of the campaign before scoring the winner against Manchester United last time out, with Shola Ameobi coming in.
Mauricio Pochettino selected defender Jos Hooiveld in place of Jose Fonte, while midfielder Adam Lallana was surprisingly dropped to the bench alongside Morgan Schneiderlin, returning from a groin injury.
Newcastle made most of the early running and Mathieu Debuchy flashed a volley from the edge of the box narrowly wide after five minutes. The home side should have taken the lead six minutes later when Gouffran beat Paulo Gazzaniga to the ball and cut it back for Remy but the striker's close-range effort was cleared off the line by Calum Chambers.
The pressure finally told in the 27th minute as Southampton failed to defend a free kick from the halfway line and Gouffran pounced on Mike Williamson's flick-on to sidestep the goalkeeper and roll home his fifth league goal of the season from six yards out.
A rare Southampton attack late in the half forced a corner that Tim Krul punched clear as Newcastle went into the break with their lead intact.
Pochettino made two changes at the interval, with Lallana replacing Daniel Osvaldo and Schneiderlin coming on for James Ward-Prowse, and the visitors looked more threatening initially, Rodriguez scuffing a volley wide after latching on to Rickie Lambert's lofted pass.
|10/1||Newcastle are 10/1 with BetVictor to finish in the Premier League's top six|
Steven Davis hit the post with a fine volley from range just after the hour mark but Newcastle failed to heed the warning.
Rodriguez broke from just inside the hosts' half and played a one-two with Davis before rolling the equaliser past Krul in the 65th minute.
Huge chances went begging at both ends within a minute, as first Lambert failed to get enough power in his close-range header and then Remy blasted high and wide when he had only Gazzaniga to beat, the keeper having given it straight to him.
Referee Mike Jones required some treatment in the closing stages after Moussa Sissoko accidentally struck him in the face and tensions flared between both benches late on in a dramatic finish to the game both on and off the pitch.