The match was drifting until the Hammers goalkeeper attempted to turn away from Sadio Mane, only to be caught out and handle outside the box as he attempted to make amends.
It led to the Spanish goalkeeper receiving a straight red card and his team having to withstand a barrage of attacks for the best part of 30 minutes - a feat Sam Allardyce's men impressively managed, defending manfully to hold Saints to a 0-0 draw.
This was a big chance missed for Ronald Koeman's Champions League hopefuls, who had 20 shots over the course of the evening without finding a breakthrough.
Saints dominated from the outset, with Mane and Florin Gardos seeing goalbound efforts denied in a one-sided first half.
A blocked Morgan Amalfitano effort was the best West Ham could muster in an opening period in which referee Craig Pawson was given abuse by the St Mary's crowd.
It did not take long for the official to find himself back at the heart of things in the second half as he decided not to give Mane a second yellow card minutes before sending off Adrian.
The Hammers goalkeeper inexplicably attempted to turn the pacey winger, only to be caught out and handle the ball outside the box as he attempted to make up for it.
It led to a deluge of Saints attack but West Ham held firm, with impressive defending, wayward finishing and some fine saves from Jussi Jaaskelainen delighting the 3,237 visiting fans.
West Ham certainly ended the match better than they started it, thanks in no small part to their late arrival at St Mary's.
Steven Davis' block to stop a fizzing Amalfitano drive was their only clear chance of a first half in which they had to defend resolutely.
Mane was first to threaten, impressively bursting past the Hammers' backline and forcing Adrian into action
The Spanish goalkeeper smothered the effort but Eljero Elia would have turned the loose ball home was it not for Carl Jenkinson hacking off the line.
Cheikhou Kouyate was next to make a timely intervention, preventing a dangerous Gardos header from finding the net.
Elia struck just wide from 20 yards after cutting inside past Jenkinson, although most moves were breaking down before Saints could get a telling shot away.
Mane curled just wide of Adrian's goal after neat interplay on the edge of the box involving Elia and Graziano Pelle.
Attention turned to referee Pawson as half-time approach, with Mane and Jose Fonte both booked for challenges compounding a number of incorrect calls from the officials.
Enner Valencia saw a deflected strike easily dealt with by Fraser Forster in that period - his last contribution of the night as Matthew Jarvis was introduced for the second half.
Play was slow to get going after half-time, with the first flash point a wild, raised foot from Carlton Cole which left Maya Yoshida with a cut below his eye.
Stewart Downing saw an effort from the edge of the box blocked by Gardos after the visitors countered following a tame Pelle effort, before Allardyce introduced Andy Carroll in a bid to change things.
The dynamics certainly did alter soon after, with Mane avoiding a second booking for a late challenge on Aaron Cresswell before playing a key role in Adrian's red card.
The West Ham goalkeeper attempted to turn away from the Senegal international, only for the winger to get a foot on the ball
The pair battled for it, only for Adrian to panic and flick the ball away with his hand outside the area, leading Pawson to dish out a straight red card.
Jaaskelainen replaced Cole in time for the resulting free-kick, which Dusan Tadic could only fire into the wall.
The remaining half-hour was one-way traffic, with Pelle blazing over after cutting inside before a Tadic flick was squeezed out.
Nathaniel Clyne was denied by a block as Saints continued to push for a winner, with Koeman introducing Filip Djuricic for his debut in a bid to do just that.
Yoshida headed over from close range and Jaaskelainen pushed a Jose Fonte strike wide as Saints upped the ante, with Tadic then denied by the back-up goalkeeper before the final whistle.
Source : PA