Substitute Marian Pahars ended Southampton's goal drought to snatch a share of the points at Newcastle.
The Latvian striker came off the bench to level 10 minutes from time and score his side's first goal in six matches under caretaker boss Stuart Gray.
Kevin Gallacher had put misfiring Newcastle in front with a well-executed 26th-minute lob, but the home side were far from convincing, and indeed, could have ended up with nothing to show for their efforts on a night when the visitors passed up a series of glorious opportunities.
Southampton - now without a win in six games - showed the greater determination and the greater quality, and but for a fine first-half save from Shay Given, could even have taken all three points.
It was the visitors who went closest to breaking the early deadlock on 23 minutes when Marsden dived to send in a goal-bound header from Kevin Davies' cross which Given brilliantly clawed out of his top corner.
The Republic of Ireland goalkeeper was in action again two minutes later to collect Hassan Kachloul's well-struck effort, but it was from his clearance that the home side went in front.
Carl Cort got up well to flick on the bouncing ball and catch the Saints' defence square to allow Gallacher to lift a shot over the advancing Jones. Southampton came back and had a number of chances, but Newcastle failed to heed the warnings and the equaliser duly arrived 10 minutes from time after Davies crossed from the right for the unmarked Pahars to head past Given.
The home side almost regained the lead within two minutes as Gallacher and Cort caused problems in the Southampton box.
Newcastle: Given, Barton, O'Brien, Dabizas, Quinn, Lua-Lua, Speed, Acuna, Bassedas (Hughes 86), Cort, Gallacher (Ameobi 86). Subs Not Used: Harper, Cordone, Stephen Caldwell. Booked: Lua-Lua, Speed. Goals: Gallacher 26.
Southampton: Jones, Dodd, Lundekvam, El Khalej (Benali 53), Oakley, Marsden, Tessem (Pahars 71), Kachloul, Davies, Beattie (Rosler 79), Bridge. Subs Not Used: Moss, Le Tissier. Booked: Davies. Goals: Pahars 81.
Referee: S Lodge (Barnsley).