Japhet Tanganga and Zian Flemming gave Neil Harris the perfect start to his fourth spell at Millwall as they upset Southampton 2-1 at St Mary’s.

Harris returned to the Den for his second stint as manager, having become the club’s all-time leading goalscorer over two spells as a player, this week after Joe Edwards had been sacked.

And he began this tenure by stunting a run of just one point in seven games after Tanganga’s header and Flemming’s penalty kept the Lions out the relegation zone.

Southampton have now lost three of their last four matches to lose touching distance in the automatic promotion race – all seven of their league defeats this season have come in either September or February.

Harris’ newest era at the club began in perfect style. He had already received a homecoming reaction from the loud away fans, before celebrating an opener inside five minutes.

George Saville floated a tantalising free-kick into the heart of the penalty box, where Tanganga had freed himself from his marker to bravely head in before getting a blow in the back from goalkeeper Gavin Bazunu.

It was the Tottenham loanee centre-back’s first professional goal.

The goal was accompanied by a chant of “Super Neil Harris” as Millwall fans made it clear they supported their fourth boss of the campaign.

Southampton dominated possession and started to create chances. Tanganga continued his impressive streak by leaping back onto his own goal-line to thwart an Adams header, while David Brooks curled wide.

Adams converted a header in the 34th minute to level the game, the striker glancing Stuart Armstrong’s perfectly-weighted cross in for his 11th goal of the season.

Brooks had an effort cleared off the line, by Shaun Cooper, before the Lions regained the lead two minutes before the break when former Southampton striker Michael Obafemi’s shot cannoned into Jan Bednarek’s arm.

Dutchman Flemming converted the penalty, via the post, for his seventh goal of the season.

It meant Saints had conceded two goals for the third successive home match.

Southampton reorganised at the break and produced three chances within the first four minutes of the restart.

Kyle Walker-Peters and Stuart Armstrong tried their luck from outside the box, but fired over, before Adams flicked over from close range.

Joe Rothwell came off the bench and should have equalised when he met a loose ball on the penalty spot, but he tamely skidded a shot straight at goalkeeper Matija Sarkic.

Sarkic was finally forced into a difficult save in the 89th minute when he swooped low to keep out Adam Armstrong’s header.

However, Millwall held on to provide Harris with the perfect start and give the manager a double over Southampton – having beaten them in the Carabao Cup when he was Gillingham boss in August.