
Daniel Peretz produced a string of outstanding saves, while James Ward-Prowse impressed on his return to London Stadium against his former boss.
Lewis Dobbin opened his Saints account with a crucial goal in the absence of Cyle Larin, while Leo Scienza’s role under Tonda Eckert raises questions.
With Saints now just three points off the automatic promotion places, here are five talking points from a memorable afternoon in East London...
Peretz produces show-stopping performance
Any team visiting the most lethal attack in their league knows they will need their goalkeeper to be at his best if they are to escape with a victory.
This was certainly the case for Saints, with Daniel Peretz making 11 saves and delivering a man-of-the-match performance despite conceding twice.
There was an acrobatic stop against Max Kilman in the first half, his long-range thunderbolt tipped onto the bar and a point-blank save in added time.
Peretz's reflexes were the difference between three points and one, or even none, and drew unprompted praise from both managers at full-time.
The Israeli did look shaky coming to claim crosses in a packed penalty area, and his distribution can at times leave something to be desired.
But he proved once again why he is one of the best goalkeepers in the Championship, leaving West Ham fans agonised by his performance.
Daniel Peretz was named Man of the Match (Image: PA)
Saints prove they have genuine promotion credentials
Although West Ham had not quite hit their stride this season, all of the attacking data points to them being the clear best team in the league.
Saints could have ended the day eight points adrift of the top two, had they been beaten by a Hammers side looking to climb into first place.
Instead, they are just three points behind Swansea in second, with the Welsh outfit being hammered 5-0 by upcoming opponents QPR.
The exact specifics of the table are not too important with 34 games to play, but Saints already came into this season chasing minus four points.
They also spent the entire second half of last campaign making up for a poor start. Eckert's entire Saints tenure has been chasing down the pack.
This result keeps Saints within one result of where they want to be, as well as proving to themselves that they are genuine title contenders.
Ward-Prowse dictating on his return to London Stadium
West Ham boss Nuno Espirito Santo has been a successful manager in the Championship and Premier League, with Wolves and Nottingham Forest.
But his snap judgement of James Ward-Prowse's usefulness has cost the former Saints captain and England player two twilight seasons of his career.
The 31 year old's return to St Mary's, having found it genuinely difficult to leave in a £30million deal three years ago, has seemingly rejuvenated him.
And when it came to Ward-Prowse's return to London Stadium, to face the boss who has become something of a foe, the pressure was on.
Operating in the engine room, he broke up play, launched counter-attacks, and helped manage the emotional temperature in a hostile environment.
Ward-Prowse is an ultimate professional in his media interviews, but even he admitted that victory felt a little bit sweeter against his former side.
James Ward-Prowse was very impressive (Image: Matt Watson / Southampton FC)
Dobbin stepping up to ease striker concerns
With starting striker Cyle Larin sidelined through injury, Lewis Dobbin took the chance to ease any concerns with an impressive all-round performance.
The 23 year old should have already scored at least one against Bolton last time out, but he opened his Saints account with the crucial third goal.
Saints had been under significant pressure since going two ahead inside 11 minutes, with West Ham pulling one back and going close to equalising.
It was an easy finish for Dobbin, converting from close range after Leo Scienza's saved shot, though he did hit the post with a tougher chance later.
But it was his tireless running and pressing from the front which showed he can offer a dynamic focal point in attack, even with a smaller frame.
Sporting director Johannes Spors believes Dobbin was the best young Englishman in the league last season. We had not seen evidence until now.
Scienza clearly no longer an undroppable star
Leo Scienza was the club's official Player of the Season for 2025/26, and he was second in the voting for the Southern Daily Echo's Player of the Year.
He is one of the most talented players in the Championship, and Saints are very fortunate to still have a winger of his quality in their ranks.
But his role appears to be reducing, or at least changing, with a benching and two early substitutions in the four fixtures since the international break.
Scienza is still contributing. He was involved in moves for Kuryu Matsuki and Dobbin's goals at West Ham, and he set up loads of chances against Bolton.
However, it is becoming increasingly clear that Eckert does not entirely trust the Brazilian to do the required defensive work in specific game states.
He prefers Sam Edozie in moments that require discipline, such as the second half at London Stadium. Scienza is still important, but not untouchable.
Leo Scienza's minutes have dropped recently (Image: PA)