Saints gave their survival hopes a massive boost as they won only their second away game of the season in the Premier League at relegation rivals Aston Villa in controversial circumstances.
The 1-0 victory at Villa Park was secured by Rickie Lambert’s first half penalty but the home team were furious about the award of the spot kick with suggestions that Jay Rodriguez went down without any contact.
The only bad news of the day was a Luke Shaw being carried off with a serious looking knee injury.
The harsh reality for Villa is that they have now taken only one point from their last five league games and look set for a season-long battle to stay up.
It completed a miserable week after the Capital One Cup semi-final, first leg setback at Bradford.
The defeat further emphasised the need for Paul Lambert to bring in reinforcements during January although he indicated yesterday that there will not be major funding available.
Although the penalty award was highly debatable, Villa were well below par in the opening 45 minutes and looked vulnerable on the counter-attack.
They improved during the second half with Christian Benteke and Andreas Weimann posing a threat.
But a combination of the woodwork, poor finishing and fine saves from Artur Boruc meant they could not pierce the Saints rearguard.
Saints have now collected 17 points from their last 11 games - a sharp contrast to losing eight of their initial 10 games back in the top flight.
They were well organised at the back and went forward with purpose with Rodriguez a threat with his pace.
Benteke looked sharp in the early stages and had a shot on the turn blocked by Jos Hooiveld at the expense of a corner.
The Belgium international was then only just too high with a dipping effort from the edge of the Saints box.
But Villa were almost caught-out on the counter-attack after Lambert's first time pass found Rodriguez in yards of space.
He cut into the box and slid the ball across Brad Guzan but Villa skipper Ciaran Clark was on hand to clear.
Saints left-back Luke Shaw ventured forward and his low shot had Guzan scrambling across his line but was inches off target.
Puncheon created space for himself inside the Villa box after a a neat turn and shot over when he should have at least tested Guzan.
But then came the hotly-contested spot-kick which put the Saints ahead.
Stevens appeared to make no contact on Rodriguez before he went to ground just inside the box.
Villa protested in vain and Lambert sent Guzan the wrong way from the spot for his ninth goal of the season.
Shaw was finding plenty of space to venture forward and Guzan blocked his shot from a narrow angle.
Lambert brought on Barry Bannan for Holman at the start of the second period and his side showed more purpose.
Artur Boruc parried Andreas Weimann's left-footed effort and then Benteke hooked the ball over the bar after Artur had denied Stevens.
But Saints still threatened danger and Clark again had to be alert to halt Rodriguez's surge forward.
Guzan was relieved when Puncheon crashed a fierce low drive against the post.
Villa staged a late rally and Boruc kept out Benteke's header.
But he was powerless to stop Nathan Baker's header which crashed against the bar from substitute Barry Bannan's corner.
Benteke then shot wide after Boruc had bravely saved at the feet of Gabriel Agbonlahor as the Saints survived to seal their second away win of the season.