Southampton0 - 1Swansea

Premier League, Southampton vs Swansea: Defeat for the home side was compounded by Ryan Bertrand's sending off late on for a reckless and dangerous challenge

This was only a first Premier League defeat in seven matches for Southampton but it was still hard not to escape the suspicion that this weekend may come to represent a pivotal moment in what has been an inspired push for Champions League football.

While Manchester United, Arsenal, Liverpool and Tottenham all continued their marked revival since Christmas, the limitations and comparable lack of firepower in Southampton's squad were evident in defeat here.

Yes, they were largely dominant in possession but, with Graziano Pelle and Dusan Tadic now struggling to attain their previous standards, they only rarely looked like scoring.

They must also now do without Ryan Bertrand for three matches after he was sent off for a dangerous scissor challenge that grazed only the ball and left Swansea winger Modou Barrow requiring a stretcher to leave the pitch. Bertrand exchanged angry words with Swanseamanager Gary Monk as he headed for the dressing room in the apparent belief that the protests from the away bench had influenced Mike Oliver in showing a straight red card.

United have now leapfrogged Southampton into third while Arsenal hover in fifth on the same points and only one goal adrift. Both teams could actually have done with Jack Cork amid various injuries but, with the former Chelsea midfielder looking down having completed his £3million move to South Wales, the match quickly settled into a pattern.

Harrison Reed and Steven Davis assumed control of central midfield and Southampton controlled possession but clear chances were scarce. Southampton's main threat actually derived from the flanks whenever Nathaniel Clyne and Bertrand burst forward from their full-back positions. This was evident inside 10 minutes when Tadic released Clyne, whose cross from the byline found an unmarked James Ward-Prowse only for Lukasz Fabianski to save brilliantly with an outstretched leg.

Southampton are hoping to sign Feyenoord's Tonny Vilhena and Serbian attacking midfielder Filip Djuricic on deadline day of the transfer window tomorrow, with the limitations in evident in Ronald Koeman naming only six of his allotted seven substitutes. Swansea were also depleted and lost Marvin Emnes to injury in the 16th minute.

Their only real moment of first-half menace was then Bafetimbi Gomis volleyed onto the roof of Fraser Forster's goal. As well as Clyne, Eljero Elia's crossing was a frequent threat and one excellent ball provoked a saving clearance by Neil Taylor of equal quality just as Tadic waited to pounce.

Elia again almost unlocked Swansea in the second-half with some wonderful skill to beat Kyle Naughton and drive into the penalty area only for Southampton's entire front line to miss his cross.

Ward-Prowse also had several sights of goal but Fabianski remained solid. Swansea continued only to attack sporadically but might easily have taken the lead when Jonjo Shelvey was permitted licence to roam deep into Southampton's half and smash a low shot to the right of Forster and off the outside of the post.

Southampton did not learn their lesson. They had been missing their usual midfield screen of Victor Wanyama and Morgan Schneiderlin and Shelvey was again permitted space in front of the back four. Ward-Prowse was nowhere to be seen, Davis did try to scramble back but wasunable to prevent Shelvey from directing his finish beyond Forster.

Koeman had few options off the bench but did introduce Sadio Mane, who had only returned on Thursday to England following the African Cup of Nations. He duly almost equalised in the 87th minute but, having twice beaten Fabianksi, had two shots cleared off the line by Ashley Williams.

Pelle was also presented with a wonderful chance in injury-time to salvage a draw but smashed his volley high into the stands.