Barnsley were cruising to the win despite blowing a string of scoring chances, but came within a whisker of defeat as Southampton finished in style.
Barnsley had a flying, wind-assisted start when they swept into the lead after just 16 seconds.
A cross by Jamal Campbell-Ryce had the Southampton defence in a panic and the ball grazed the head of Brian Howard and broke to midfielder Sam Togwell.
He stretched out his right leg and volleyed an ungainly shot over Kelvin Davis who had strayed off his line.
As both sides struggled to master the atrocious conditions of driving rain and a swirling wind, chances were few and far between.
Southampton - who were beaten 3-2 by Barnsley at St Mary's in August - caused concern in the home defence with a series of testing crosses and set pieces.
But the only real chance of note early on came when Adam Hammill produced a shot out of the blue that went close from 18 yards out.
The visitors lived dangerously when Howard angled an inch-perfect pass for Kayode Odejayi and the big striker rammed a shot that Davis could only parry and, when Alan Bennett cleared, Marciano van Homoet hit a 25 yarder that was just over.
But in the 34th minute, Barnsley doubled their lead when Campbell-Ryce broke down the right before blasting a fierce shot from 22 yards which beat Davis in spectacular style.
Four minutes later, the home side should have put the game beyond Southampton when Odejayi beat the offside trap and, with only Davis to beat, he scooped his shot over the top.
Four minutes after the restart, Campbell-Ryce came close to a second eye-catching goal when he cut in from the right and blasted another fierce shot that Davis did well to beat away.
And full-back Bobby Hassell might have added a third for the home side two minutes later but his header from Howard's cross was blocked.
But on the hour Saints pulled one back when Wright-Philips, who had arrived from the bench a minute earlier, claimed his sixth goal of the season.
Barnsley centre-back Lewin Nyatanga was caught out and Wright-Phillips produced an emphatic finish with a crisp low shot.
And ten minutes later, Wright-Phillips added the second as Southampton kept up the pressure.
He latched onto a loose ball and rifled in a low shot for the equaliser.