Southampton set a new club record of 21 games without defeat thanks to a 3-1 victory on Russell Martin's first return to Swansea City.
The Saints climb to second in the Championship having outclassed Swansea in the first half, Che Adams putting them ahead from close range only six minutes in.
Will Smallbone tapped in the second goal before Swansea responded against the run of play through a Jamie Paterson header.
But Southampton quickly re-established their control of the contest as Flynn Downes' 20-yard drive deflected into the net.
Swansea rallied in the closing stages as substitute Jerry Yates and Paterson both hit the woodwork, but their failure to take the late chances allowed Southampton to hold on for three points with comfort.