Southampton’s revival under Ralph Hasenhüttl was brought to an abrupt halt on a night when Felipe Anderson delivered the sort of performance that suggests West Ham United have a new hero in their ranks. The Brazilian was outstanding as he scored twice in six minutes to turn this game on its head and extinguish any hopes Southampton had of putting some distance between themselves and the relegation zone.

Nathan Redmond’s early second-half goal – bundled over the line with his arm – put Southampton ahead but that lead lasted for 168 seconds. Felipe Anderson scored only once in his opening 10 Premier League games after joining from Lazio in a club-record £36m deal but the 25-year-old has been making up for lost time since. He hauled West Ham level here with a terrific shot from just outside the area and then made it seven goals in his last nine matches by finishing off a superb counterattack with a beautifully placed winner.

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That double blow left Southampton in a state of shock from which they never really recovered. Hasenhüttl, who had won two of his previous three games in charge, admitted his players looked tired in the closing half an hour and also expressed his frustration with the way that “old behaviours were seen today”. Southampton have lost more points from a winning position this season than any other Premier League club, which is why the manner of this defeat felt all too familiar.

West Ham, on paper, were welcome opponents. Manuel Pellegrini has a major injury crisis on his hands – he is without 10 senior players and was able to name only six substitutes here – yet the visitors looked the more accomplished side throughout. Declan Rice was particularly impressive in the centre of midfield in the first half, when Southampton faded after Danny Ings stabbed an early chance into the side-netting, while Felipe Anderson became more and more influential for West Ham and was unlucky not to finish the game with a hat-trick.

Southampton, however, were entitled to question whether his second goal should have come about. Television replays showed Rice wrestling with Jan Bednarek in the West Ham area in the lead-up to the breakaway that ended with Michail Antonio releasing Felipe Anderson clear on goal. “I haven’t seen it. But I heard it,” Hasenhúttl said, when asked about the penalty claim. “Maybe with VAR it can be a penalty for us. It could make a big difference for us in that moment. But we try to look at ourselves first and find the mistakes we made.”

Facebook Twitter Pinterest Declan Rice turns away from Southampton’s Oriol Romeu in what was an impressive performance by the West Ham midfielder. Photograph: Glyn Kirk/AFP/Getty Images

The Southampton manager was particularly disappointed in that respect. “We didn’t have our best evening; too many players didn’t perform like they did maybe last week or the week before,” he said. “And you see what I tell my players, that it’s the Premier League and, if you make easy mistakes like we did on the second goal, then you don’t deserve to win. The first goal we could also defend better. It was too easy how we gave our 1-0 lead away.”

Pellegrini, in contrast, could reflect on a hugely satisfying night, especially given that long list of absentees. West Ham have now won five out of their last six league games and they are up to ninth in the table, with 27 points on the board – not bad for a team that have been playing catch-up after losing their first four fixtures.

Felipe Anderson is clearly their star attraction, although Pellegrini was guarded in his praise. “I think he will continue improving,” West Ham’s manager said. “He still loses too many balls, maybe because he must understand the Premier League is difficult if you keep the ball in your feet. But in every game he makes important plays and that’s the most great thing that he has.”

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The match had been a slowburner and precious little happened before the break, apart from Lucas Pérez squandering a golden chance for West Ham. It came to life after the interval, however, when Redmond scored within five minutes of the restart. Lukasz Fabianski initially denied the Southampton winger, who was played onside by Grady Diangana, and the West Ham goalkeeper also thwarted Oriol Romeu. Redmond refused to give up, though, and controversially nudged the ball over the line.

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Felipe Anderson then equalised with a 22-yard shot that flashed inside Alex McCarthy’s near post. If McCarthy’s positioning was questionable on that occasion, there was nothing Southampton’s goalkeeper could do to prevent West Ham’s second. Antonio tore upfield and picked out Felipe Anderson, who took a couple of touches to steady himself before steering a rising shot into the far corner. Although Fabianski had earlier denied Stuart Armstrong and later kept out Mario Lemina’s effort, Pérez and Felipe Anderson both had chances to add a third for West Ham.