Antoine Semenyo did brilliantly to beat his man on the left wing before picking out Lewis Cook on the edge of the box. Cook’s curling effort towards goal was met by Dango Ouattara, who got the final touch to divert the ball past Ramsdale.
And just before half-time, Bournemouth added a third. Semenyo was the provider this time, as he collected a loose ball on the edge of the box before firing a low shot into the bottom corner to give Bournemouth a comfortable lead at the break.
Southampton did manage to pull a goal back in the second half through Harwood-Bellis, but it was too little too late as Bournemouth held on for a deserved victory.
The win will be a huge boost for Bournemouth as they look to climb up the table, while Southampton will be left searching for answers as they continue to struggle in the Premier League.