Record signing Dani Osvaldo scored his first for the south coast club when he sent a left-foot shot beyond keeper Julian Speroni in the 47th minute.
The Italy international then won a free kick 90 seconds later for Rickie Lambert to grab his first Premier League goal since the opening day of the season.
Lambert struck his effort perfectly from 20 metres, lofting the ball over the wall and in off the post.
"I was desperate to get on the scoresheet sooner rather than later," the England centre forward told reporters. "I am over the moon.
"We knew if we kept going, kept passing around the box, we would get chances and those chances would go in."
Lambert paid tribute to Osvaldo, a 12.8 million pounds ($20.64 million) buy from AS Roma in August.
"Dani did fantastically for his goal and it has given him the confidence he needs," said the England striker.
It was the first time Southampton had scored two goals in a league game this season and it lifted the team to fourth place in the table.
"To be fourth ... it's very nice, very nice ... let's try to stay there," said Lambert.
"It's a hard league. I won't be too fussed if I don't score 15 like last season so long as the lads do their stuff."
($1 = 0.6203 British pounds)