As Bournemouth continued to sit back, Sulemana collected a pass from Paul Onuachu to drill his first Premier League goal since May 2023 into the bottom right corner.
Defeat for bottom club Southampton was their 20th of a miserable top-flight campaign as near neighbours Bournemouth deservedly claimed local bragging rights and a first league double in this fixture.
Creative midfielder Christie conjured a fine assist for Dango Ouattara's 14th-minute opener before swiftly firing home a superb second to help put the Cherries on the cusp of the Champions League qualification spots.
RYAN CHRISTIE starred as Bournemouth soared to fifth in the Premier League table by pushing south-coast rivals Southampton a step closer to relegation with a 3-1 win at St Mary's.
Ouattara claimed the early breakthrough, finding space between Southampton centre-backs Jan Bednarek and Nathan Wood to glance home via the far post with his shoulder following Christie's delightful delivery from the left.
