ALBION broke their Barclays Premier League record for points in a season in style with a three-goal romp at St Mary’s Stadium - which saw three red cards.
Marc-Antoine Fortune opened the scoring in the sixth minute with his second strike of the season to set up the Baggies’ 14th top-flight victory this term – another Premier League best.
Romelu Lukaku doubled the lead and took his season’s tally to 14 in the 67th minute and ten minutes later he turned supplier as he teed up Shane Long to move into double figures for the campaign.
There was an ill-tempered finish to the south coast clash as Saints substitute Gaston Ramirez was sent-off for elbowing Long and Fortune quickly followed him down the tunnel for retaliating with a push in the Uruguayan’s face.
Things went from bad to worse for the hosts when they were reduced to nine men, with Danny Fox given his marching orders for a two-footed lunge on Steven Reid.
The victory moved the Baggies onto 48 points - one more than they have amassed in each of the last two seasons.
Albion were backed by more than 3,000 fans at St Mary’s – the majority of whom made the long journey on free coach travel provided by the club.
Steve Clarke made three enforced changes to his starting XI as Reid, Liam Ridgewell and Long were all elevated from the bench.
The men to make way were injured trio Billy Jones - who after sustaining a gashed leg in last weekend’s 1-1 draw with Newcastle was among the subs - Goran Popov - who picked up a knock in training - and Chris Brunt - who suffered a knee injury against the Magpies.
Mauricio Pochettino named an unchanged Saints side but took the Baggies’ 4-2-1-3 formation into account when setting out his men, as the hosts looked to extend their six-game unbeaten run.
Albion came flying out of the blocks and Lukaku out-stripped Jos Hooiveld from Reid’s ball down the right in the sixth minute to burst into the box and force Artur Boruc into a save with his feet.
From the resultant Graham Dorrans corner, Gareth McAuley headed the ball forward and Lukaku nodded it on to Fortune, who saw his initial close-range effort stopped by Boruc before bundling the rebound over the line to give the visitors the lead.
Southampton replied with a spell of pressure and Jonas Olsson needed to be at his best to block Morgan Schneiderlin’s tenth-minute goalbound effort from the edge of the box.
The next effort also came from the hosts as Jay Rodriguez headed Rickie Lambert’s cross just over the bar from 15 yards.
Albion turned on the style on 19 with a flowing move to cut open the Saints defence. Ridgewell, James Morrison and Dorrans combined with some outstanding one-touch passing to put Lukaku through on goal – but again the on-loan Chelsea striker was thwarted by Boruc.
Dorrans delivered a sublime free-kick to the back post for Olsson in the 28th minute but the Sweden international tried to pick out Lukaku on the volley when he had a clear sight of goal from six yards.
Ben Foster was called on to make an important save four minutes later as he stood up big to tip over Nathaniel Clyne’s 12-yard drive after the Southampton right-back pounced on a loose ball.
Three minutes before the break, Reid launched Dorrans off on a counter-attack and he slotted the ball to Long, whose ambitious shot from 25 yards sailed over.
In the final moments of the half, Albion should have been two up but, after clever play between Dorrans and Long from Foster’s long kick, Lukaku fired a tame right-footed volley straight at Boruc from 12 yards.
Pochettino made a change at the break as Ramirez came on for Jack Cork and the Saints switched to a 4-4-2 line-up.
The first real threat after the break came in the 56th minute when Clyne wriggled free of Claudio Yacob’s attentions and fired a shot from a tight angle off the crossbar.
The game went quiet for a patch but the Baggies burst into life on 67. Reid found Fortune on the counter-attack and he produced a delightful turn and pass for Lukaku, who confidently rounded Boruc and slotted home to double the lead.
Three minutes later, both teams were reduced to ten men when substitute Ramirez was sent-off for elbowing Long. Fortune was also given his marching orders for pushing Ramirez in the face in response to the foul.
Lukaku cleverly burst past Clyne on the right byline on 75 and slid the ball in front of goal, where Morrison looked like adding a third until Schneiderlin’s last-ditch challenge.
Lukaku was again involved two minutes later as he slid in Long and he kept his cool to slot home under Boruc from 12 yards to make it three.
A fiery finish to the game saw the Saints reduced to nine men as Fox was sent-off for a two-footed lunge on Reid.
SOUTHAMPTON (4-2-3-1): Boruc; Clyne, Yoshida, Hooiveld, Fox; Schneiderlin, Cork (Ramirez HT); Lallana (c) (Mayuka 69), S Davis, Rodriguez; Lambert (Fonte 86). Subs not used: K Davis (gk), Forren, Guly, Puncheon.
ALBION (4-2-1-3): Foster; Reid, McAuley, Olsson (c), Ridgewell; Yacob, Dorrans;Morrison (Jones 78); Fortune,Long (Rosenberg 88), Lukaku (Thomas 85). Subs not used: Myhill (gk), Odemwingie, D Daniels, Tamas.
GOALS: ALBION – Fortune (6), Lukaku (67), Long (77).
BOOKINGS: SOUTHAMPTON - Hooiveld (foul 28). ALBION – Yacob (foul 34).
SENDINGS-OFF: SOUTHAMPTON – Ramirez (violent conduct 70), Fox (dangerous play 82). ALBION - Fortune (violent conduct 70).
REFEREE: R Madley (West Yorkshire).
ATTENDANCE: 31,946 (3,195 Albion fans).
ALBION STARMAN: Romelu Lukaku.