Isaac Hayden fired the Magpies ahead from 25 yards after goalkeeper Fraser Forster was left flat-footed before Joselu was denied from making it 2-0 by the bar.
Saints conjured up a rare home goal through Gabbiadini’s shot on the turn only for Newcastle to restore their lead 87 seconds later, Ayoze Perez finding the net from an angle after Forster had spilled the Spaniard’s initial shot.
Newcastle were denied victory when Gabbiadini, starting for the first time since 9 September, scored from the penalty spot after Florian Lejeune needlessly bundled over Shane Long.
Southampton had failed to score in eight of their past nine Premier League home games – and they failed to muster a shot on target in the first half in this game.
Yet Mauricio Pellegrino was rewarded for his decision to restore Gabbiadini to the side as the Italian scored twice in 26 minutes to deny Newcastle a rare top-flight away win.
It looked like another frustrating game as Dusan Tadic, unmarked inside the six-yard area, headed tamely over the bar with the match goalless before Hayden fired the visitors ahead.
