Southampton manager Ronald Koeman said he was "in shock" after his side continued their outstanding start to the season with an 8-0 thrashing of Sunderland at St Mary's.

Prior to the campaign, many pundits predicted the Saints would struggle after manager Mauricio Pochettino joined Tottenham Hotspur while key players such as Luke Shaw, Rickie Lambert, Adam Lallana, Dejan Lovren and Calum Chambers also moved to rival Premier League clubs.

But Koeman has done more than stop the rot, with this victory leaving Southampton third in the table, with only champions Manchester City and leaders Chelsea above them in the standings.

Graziano Pelle's double, as well as goals from Jack Cork, Dusan Tadic, Victor Wanyama and Sadio Mane, plus two Sunderland own-goals, saw Southampton to their biggest-ever victory in English top-flight football.

"I'm very pleased. Still a little bit in shock. That 8-0 is not a normal result," said 51-year-old Koeman, one of the leading defenders of his generation in a career that included spells with Ajax and Barcelona as well as 78 caps for the Netherlands.

"I was surprised after 20 minutes about the score. 2-0 up and we didn't start the game well.

"Sunderland were dominating and we had problems. Lucky by the first one, the own goal, gave us a little bit more confidence and we wake up after that.

"I'm very proud about the second half. We have 17 players out in the international break and if you show that ambition until the last second it is great. That was important. We played great football, we scored great goals and it was a great afternoon."

One superstition in English football is that being named manager of the month means your team is bound to lose its next fixture.

Chelsea manager Jose Mourinho said he was glad Koeman, not him, had won the latest Premier League version of the award but the delighted Saints boss said: "Maybe I thank Mourinho for that, he gave my players motivation.

"I'm joking of course. I like Mourinho and I look forward to playing Chelsea."

Meanwhile Sunderland manager Gus Poyet was left contemplating one of his worst days in football.

"Where do I start? First, it was the most embarrassing (moment) I've had on a football pitch without any doubt," he said.

"I feel sorry for the supporters," he added of the more than 2,500 Sunderland fans who made the long journey down from the north-east.

"It's going to be a difficult week. The players who are on the pitch next week are going to do something about it.

"I don't think I want to watch that again. Sometimes I make clips. I wouldn't have time to make as many clips as I need. Maybe the players will watch it. Maybe it will be good therapy for them to watch themselves."