The hosts took the lead with 20 minutes on the clock when Rickie Lambert got on the end of a corner to head in at the back post.
The Saints sealed the points just before the break as Lambert unselfishly nodded the ball back across goal for Jay Rodriguez to head in.
Here, Sports Mole takes a closer look at the action between the sides at St Mary's Stadium.
On target 6
On target 0
Was the result fair?
Make no mistake, this was one of the most one-sided matches that the Premier League is likely to see this season. Southampton not only dominated throughout but they absolutely dismantled Fulham. Where the hosts were superb, the visitors were abject. If anything, the Saints could have had about another two or three goals to their tally come the final whistle.
To a man, the Saints were brilliant. Their passing and movement was of an incredibly high standard, while the fitness levels on show were something to marvel. Mauricio Pochettino's side never took their foot of the gas, slicing and dicing Fulham into submission. But for some wayward finishing, this could have been a rout and no one would have complained.
Quite simply, this was horrible from the Cottagers. From the first whistle they never caused Southampton any problems, as demonstrated by a big fat zero for their shots on target. A worrying amount of players for the away side looked like their heads were still on the team bus as their sluggish, lethargic display set them up for a comfortable beating. If they continue to perform like this then it will be a very long season indeed.
Sports Mole's man of the match
Adam Lallana: There was not a busier player on the pitch than Southampton midfielder Lallana. He was at the heart of nearly every attack for his side and kept running until the final whistle. To cap what was a fine evening, he played an integral part in the Saints' second goal with a delightful cross for teammate Rickie Lambert to head onto scorer Jay Rodriguez.
Philippe Senderos had a nightmare opening few minutes, almost gifting Southampton two goals. The first mistake was the worst as he was caught in possession on the edge of his own box before Morgan Schneiderlin saw his shot cleared off the line.
There were one or two decisions from Andre Marriner that were plain wrong, but overall the official allowed the game to flow with a routine display out in the middle.
Southampton: The Saints continue their Premier League campaign next Saturday with a trip to Stoke City.
Fulham: The Cottagers are back in action on Tuesday with a trip to Leicester City in round four of the League Cup.