Off the back of being named September's Manager of the Month on Friday, Ronald Koeman guided Southampton to their biggest ever win in the top flight, as Saints beat Sunderland 8-0 this weekend. Southampton, who last won by the same scoreline against Northampton Town in the Third Division South way back in December 1921, now become only the fifth team since the inception of the Premier League to win by at least an eight goal margin. They follow Manchester United's 9-0 win over Ipswich in 1995, along with Newcastle, Tottenham and Chelsea who have all won by eight in the last two decades. Koeman had described Sunderland as "strong opponents with a good defence" in the build up to the game, while after the match he told the press that: "I was not happy with how we started the game. Sunderland was the dominant team". It took a spot of bad luck for the Black Cats after 12 minutes to turn things around. Defender Santiago Vergini put the ball into his own net with the kind of curling volley into the top corner that would make a centre forward proud. The bizarre own goal from the Argentinian, on loan from Estudiantes, provoked manager Gustavo Poyet to comment: "Even if you watch that 20 times, you don't know how it can happen." From then on Southampton took control of the game. Midfield dynamo Morgan Schneiderlin completed over 90% of his passes as Saints dominated the centre of the park, while September Player of the Month Graziano Pelle followed up his debut international goal earlier in the week with the second and fifth of the game, taking his total for the season up to 7. It was fellow summer signing Dusan Tadic, though, who impressed most of all. Any pre-season worries that last year's Southampton Player of the Year Adam Lallana would be difficult to replace have proved unfounded thanks to the Serbian midfield star who is proving worth every penny of his £10.9 million transfer fee. Tadic constantly teased and tormented the Sunderland defence, crossing for Jack Cork to stab home Southampton's third late in the first half. Later, with Saints already 5-0 up, Sunderland keeper Vito Mannone rolled the ball straight to Tadic's feet 30 yards out and the midfielder made no mistake curling the ball into the empty goal. Almost as soon as Sunderland had kicked off Tadic had the ball again and set up a goal for Victor Wanyama. The win was completed when Tadic teed up fellow new signing Sadio Mane for his first goal since arriving from Red Bull Salzburg on transfer deadline day. Sunderland, who were last beaten 8-0 back in 1982 by Watford, may have been unfortunate at some points but were thoroughly outplayed overall. Mannone struggled, but largely because his defence left him badly exposed. Vergini followed his spectacular own goal with a poor sense of positioning that allowed Steven Davis to set up Pelle's first, while Liam Bridcutt also found his own net after Mannone saved from Pelle. Sunderland now find themselves in 17th place, just one place and one point above the relegation zone and rivals Newcastle who were also heavily beaten on their visit to St. Mary's. Poyet's team will have plenty of time to mull over their failings on the long journey back north, but will need to pick themselves up again before the visit of Arsenal this Sunday. Meanwhile Southampton, who now boast the league's meanest defence on top of their free scoring win this weekend, are a point better off than the equivalent stage of last season and face a relatively easy run in Stoke, Hull, Leicester and Aston Villa over their next four matches. If Saints can build on this record breaking win then there is every possibility of exceeding last year's 8th place finish and challenging for a spot in Europe next season.