Chelsea were flying after their victory at Tottenhamon on Sunday, which seemed a turning point for Frank Lampard and the evolution of his young team. It was a back-ground accident, further evidence of a maddening inconsistency.
Southampton's victory was perfectly judged and well deserved, triggered by a special first-half goal from 19-year-old Michael Obafemi and boosted by the threat of the second half at halftime. Nathan Redmond scored the goal that made the points secure – he was a thorn on Chelsea's side – but this was a team triumph, built on the firm defensive central contributions of Jack Stephens and Jan Bednarek. Midfielders Pierre-Emile Højbjerg and James Ward-Prowse were also excellent.
Chelsea have lost three of their four Premier League games at home, this one after their games against Bournemouth and West Ham – and drew blank on each occasion. Their inability to differentiate Southampton was a major concern and, despite remaining fourth in the table, it is obvious to say that they should do better against much lower teams.
The out-of-Southampton form has been better than the at-home form – they always tend to score on their travels – and when they first did it here, it was a goal to ward off cobwebs. It was a start to friction, but Obafemi injected rhythm and incision into a cameo that made Ralph Hasenhüttl jump for joy.
The Southampton coach started with Obafemi and Che Adams at the front in his 4-4-2 system; Shane Long was injured and, with an eye on Saturday's game against Crystal Palace, decided to use Danny Ings only as a substitute.
The decision came with a dividend after Højbjerg made a low pass to Obafemi, who caught it after Fikayo Tomori's failed interception attempt. Southampton had won Callum Hudson-Odoi's ball in midfield, attacking him while trying to play, and once Obafemi raised his head and the afterburners, the alarm rang in Chelsea.
Chelsea's Tammy Abraham is challenged by Southampton defender Jack Stephens. Photo: Chris Lee – Chelsea FC / Chelsea FC via Getty Images
It was the purpose with which Obafemi cut the interior, showing a lovely balance and pulling him away from Kurt Zouma, which opened the chance of throwing and the question was whether he could perform the left foot curler in the opposite corner. The answer was an emphatic yes. It was only Obafemi's fourth start in the Premier League. His second goal in the competition was a beauty.
The Southampton formation was designed to be difficult to break, leaving little precious space between the lines. Their work rate was prodigious and Chelsea suffered a lot of frustration. They fed on scraps in the first half and, on the one occasion that Alex McCarthy was forced to work on Southampton's goal, moving away from César Azpilicueta's kick after a corner from Willian, but the effort was ample. Hudson-Odoi had a shot blocked by Jack Stephens; Tomori nodded weakly after a short corner and Hudson-Odoi was guilty of a poor cross when well placed.
Lampard maintained the 3-4-3 system which resulted in a tactical masterclass on Spurs. It failed on this occasion and he switched to a quarterback at halftime, introducing Mason Mount in the offensive midfield and sacrificing Zouma.
Chelsea looked more urgent with Mount on the pitch and they pressed the front foot, but it was Southampton who carried the biggest threat on the counter, where Redmond's pace was a weapon. Kepa Arrizabalaga, at 65 minutes, denied the Reds face-to-face at 65 minutes, which seemed like a great moment, as he had beaten Antonio Rüdiger to cross low for Adams on the far post. Tomori reached to push the ball away.
Redmond would not be denied and his goal came after a long and impressive sequence of passes from his team. Stuart Armstrong tried to get away from N'Golo Kanté just for Chelsea's midfield challenge to send the ball to Redmond at the far post, and when the wing arrived before Arrizabalaga, he drove home intelligently.
Chelsea offered no more than flickers in the third attack in the second half, with Tammy Abraham shooting in the net and Christian Pulisic and Mount testing McCarthy. Hasenhüttls's full-time celebrations showed what this victory meant.