The five reasons behind Southampton's slump

Here, Press Association Sport looks at what is going wrong for Ronald Koeman's side.

Saints' best-ever start to a top-flight season began to go awry at the point many onlookers expected, with home matches against the Manchester sides, City and United, book-ending a trip to Arsenal. Those matches ended in defeats and, in the process, saw them concede six goals - as many as they had let in during the previous 12 Barclays Premier League matches.

The defeats to City, Arsenal and United were not as clear-cut as they appear. Southampton were more than holding their own at the Emirates Stadium until Toby Alderweireld was forced off, with the injury reducing Saints to 10 men for the closing stages - a numerical advantage Alexis Sanchez capitalised on to secure a 1-0 win. Even Louis van Gaal admitted United were "lucky" to leave St Mary's with three points, while injury was the catalyst to City's 3-0 win.

Morgan Schneiderlin, arguably Southampton's best player, was forced off injured midway through the match against City. With Jack Cork out ill, defender Alderweireld was pushed into midfield, unbalancing the side. Schneiderlin is now back but Cork is out for up to two months, while James Ward-Prowse is absent through a foot injury.

Graziano Pelle set the league alight with his start to life at St Mary's, but things have dried up of late. A lack of service and confidence has impacted the Italy international, who Saints have become reliant upon to lead the line. Sam Gallagher, who impressed last season, remains injured, while Emmanuel Mayuka has yet to impress at the club. Big-money acquisition Shane Long has so far been preferred in a wide attacking role.

For many of the new arrivals this is the first time they have such a hectic December. Pelle, Dusan Tadic, Sadio Mane and Alderweireld have never before played in English football, while this it is also a first taste for vastly-experienced manager Koeman.