Saints won a league match at Old Trafford for the first time in 27 years, as Dušan Tadić’s second-half goal capped a majestic away performance from Ronald Koeman’s side.
Tadić stroked home from just inside the area in the 69th minute after Graziano Pellè’s shot had come back off the post.
Juan Mata missed a couple of good chances towards the end, but Saints were good value for the win, with their defence preventing Manchester United from registering a shot on target.
Goal of the month: Sadio Mané vs Arsenal (h)
Saints emerged with all three points from their trip to Loftus Road in dramatic circumstances, as Sadio Mané scored a brilliant winner in added time.
The forward sound inside the area and crashed a left-footed shot into the roof of the net, right in front of the travelling fans.
Earlier, Fraser Forster had made one of the saves of the season to flick a Joey Barton effort that had deflected wickedly off Charlie Austin over the bar.
Goal of the month: Sadio Mané vs QPR (a)
Saints followed up their 1-1 home draw against the Blues earlier in the season with the same result at Stamford Bridge.
Diego Costa had headed Chelsea into an early lead, but Ronald Koeman’s team levelled before half-time, as Dušan Tadić converted from the penalty spot following a foul on Sadio Mané.
Saints were a match again for the London club in the second half, ensuring they went undefeated against the eventual champions during the season.
Goal of the month: Shane Long vs Burnley (h)
James Ward-Prowse scored his first ever Premier League goal for Southampton, as he converted from the penalty spot in this game.
His 56th-minute effort came after Shane Long had been fouled by Alex Bruce, and it represented only his second ever goal for the club – with the previous one having come in an FA Cup tie away to Coventry in January 2012.
Saints then wrapped up the points in the 81st minute, when Graziano Pellè fired home from Morgan Schneidetrlin’s square pass.
Goal of the month: Graziano Pellè vs Tottenham (h)
Saints secured a thumping win in their last home match of the season, with Sadio Mané writing his name into the record books.
The forward scored the fastest hat-trick in Premier League history when he netted three goals in the space of two minutes and 56 seconds during the first half.
Shane Long also netted twice in the opening half, including a stunning long-range strike, with Saints holding a 5-1 lead at the interval, before Graziano Pellè added a sixth late on.
Goal of the month: Shane Long vs Aston Villa (h)
Saints won their first European match since 1981, as they cruised past Dutch club Vitesse, at St Mary’s.
Graziano Pellè set them on the way with a thumping finish from Sadio Mané’s through pass, before Dušan Tadić added a second from the penalty spot right on half-time.
Shane Long added a third in the closing minutes, with Saints going on to win the second leg of the Europa League third round qualifier 2-0.
Goal of the month: Graziano Pellè vs Vitesse (h)
Saints grabbed their first win of the 2015/16 Premier League season with a resounding success against the Canaries.
Graziano Pellè’s first-time finish at the near post from a Sadio Mané pass put them ahead early on and, after Steven Whittaker was sent off later in the first half, the hosts took even greater control.
Dušan Tadić ensured all three points with a pair of goals after half-time, firstly firing into the top corner from close range after a fine team move, before later tapping in after a Pellè header had been saved.
Goal of the month: Graziano Pellè vs Newcastle (a)
Saints romped to victory in the third round of the Capital One Cup, with Jay Rodriguez, Sadio Mané and Shane Long each scoring twice.
Ronald Koeman’s side were 3-0 up inside 25 minutes, after Jay Rodriguez’s brilliant solo opener was followed up by a pair of Mané strikes.
Rodriguez added a penalty shortly after half-time, before Long added a further two goals.
Goal of the month: Jay Rodriguez vs MK Dons (a)
Saints earned a stunning away victory at Stamford Bridge, as they overcame Willian’s early goal to claim all three points.
The Chelsea midfielder netted with a free-kick, but the visitors were level just before half-time, as Steven Davis slammed in a right-footed shot from 20 yards after receiving Graziano Pellè’s chested pass.
Sadio Mané then broke through after the break to finish past Thibaut Courtois, before Pellè wrapped things up with a fierce strike into the far bottom corner.
Goal of the month: Maya Yoshida vs Aston Villa (h)
Saints claimed the honours in the first ever Premier League meeting between the two south coast clubs.
In a hard-fought match, they took the lead in the 31st minute, as Steven Davis raced in to side-foot home a Ryan Bertrand cross.
Five minutes later, Graziano Pellè headed in a Dušan Tadić delivery to give Saints a cushion, which was a welcome one after Victor Wanyama was sent off in the second half for a pair of yellow cards.
Goal of the month: Steven Davis vs Bournemouth (h)
Saints ended a six-match winless run in the most emphatic of fashions, as they demolished the in-form Gunners at St Mary’s.
Cuco Martina’s swerving, 30-yard wonder goal ensured they held a slender lead at the interval.
Far from being subject to an Arsenal onslaught after half-time, though, Saints continued to pile on the pressure and were rewarded as Shane Long struck twice, with José Fonte also powering home a header in between.
Goal of the month: Cuco Martina vs Arsenal (h)