Alan Shearer scored the 400th goal of his career as Newcastle saw off a struggling Southampton outfit.
Shearer scored from the spot after Calum Davenport's tug on Shola Ameobi while Saints keeper Antti Niemi went off after being hurt in the incident.
Newcastle extended their lead when Titus Bramble flicked in a shot at the near post before Peter Crouch pulled one back from close range for Saints.
Newcastle could have scored more but David Prutton almost punished them.
Prutton saw his late shot blocked as Newcastle nearly paid the price for their wastefulness.
Shearer was back for Newcastle after two months out and marked his return by sending Paul Smith the wrong way with his penalty.
Smith was on for Niemi and making his first start for the struggling south-coast club and was overworked in goal behind a poor defence.
Saints keeper Niemi was forced off injured early on
A shot from the lively Ameobi was blocked before Smith spread himself well to keep out a Craig Bellamy strike.
Kieron Dyer was the next Newcastle player to be denied by the rookie keeper who was at full stretch in tipping over his 25-yard shot.
The visitors were fortunate not to concede another penalty for Davenport's tackle on Ameobi but the home side were creating chances at will and added to their lead through Bramble.
The defender stole in at the near post to flick in a whipped free-kick from Celestine Babayaro.
Newcastle's passing and movement, along with the pace and trickery of Bellamy, Dyer and Ameobi, was proving too much for Southampton who still managed to sneak a goal back.
A Davenport knock-down was headed against the crossbar by Kevin Phillips and Crouch scored from the rebound.
Newcastle should have easily put the game out of Southampton's reach as they dominated but Bellamy steered a volley over as they failed to finish their opponents off.
And they were nearly made to pay for it when Crouch went down over a Bramble tackle only for his penalty appeals to be waved away.
Paul Telfer was left unmarked in Newcastle box and had a free header which he put disappointingly high.
Prutton's late effort almost rescued a point for Southampton but Newcastle survived after a tense finish.
Newcastle: Given, Taylor, Bramble, Boumsong,Babayaro (Hughes 86), Jenas, Bowyer, Dyer, Bellamy (Milner 75),Shearer (Kluivert 62), Ameobi.
Subs Not Used: Harper, Robert.
Goals: Shearer 9 pen, Bramble 38.
Southampton: Niemi (Smith 6), Telfer, Lundekvam, Davenport,Higginbotham, Prutton, Redknapp, Delap,McCann (Anders Svensson 66), Phillips (Ormerod 87), Crouch.
Subs Not Used: Oakley, Nilsson.
Booked: Telfer, Crouch.
Goals: Crouch 42.
Ref: U Rennie (S Yorkshire).