A sparkling performance from the Saints captain inspired Mauricio Pochettino's side to a rampant home win over Steve Bruce's Tigers
Rickie Lambert and Adam Lallana were both on the scoresheet in the first half at St Mary's Stadium as Mauricio Pochettino's men made it four top-flight wins in a row at home, while Morgan Schneiderlin and Steven Davis also made sure that Yannick Sagbo's seond half goal was only a consolation.
The home side went ahead early on, with Schneiderlin taking advantage of poor defending in the Hull ranks to head home Lambert's knock-down.
Lallana was instrumental in the second, as he looked to get onto the end of a Lambert pass, only for the onrushing Steve Harper to take him down. Lambert then emphatically converted the penalty to maintain his 100 per cent record from the spot for Southampton from 33 attempts.
Southampton's third came after 36 minutes, courtesy of Lallana himself. The 25-year-old jinked his way into the area before calmly slotting the ball past Harper from a tight angle.
Yannick Sagbo pulled a goal back for Hull early in the second half following an error from Victor Wanyama. However, any hopes of a comeback had all but disappeared by the time Steven Davis hit a low drive past Harper in the closing stages.
Hull were unchanged from their last Premier League outing, which saw them beat Sunderland 1-0, although there was no place on the bench for Robbie Brady, who continues to struggle with a hernia problem.
Southampton also named an unchanged side, but recalled Pablo Daniel Osvaldo to the squad with the Italy international having recovered from a nerve problem.
Lambert, Lallana and Jay Rodriguez started for Pochettino, following their England call-ups, while 18-year-old Sam Gallagher made his first appearance in a league squad for the club.
Southampton edged a slow-paced opening and were rewarded when Schneiderlin recorded his first goal of the season from close range after 16 minutes.
Pochettino's side doubled their lead on the half-hour mark, with Lambert converting a penalty after Lallana was brought down in the area by Harper, who was booked.
The hosts continued to demonstrate their clinical streak, edging 3-0 ahead six minutes later courtesy of Lallana's third Premier League goal of the season.
Southampton had kept clean sheets in their previous four home Premier League games, but Hull got on the scoresheet nine minutes after the break, Sagbo coolly finishing after George Boyd pounced on a dithering Wanyama, who was withdrawn soon after.
Tom Huddlestone was next to threaten with a long-range effort before Lallana forced a save from Harper after good link-up play with Lambert in the Hull box.
Substitute Davis capped off a comprehensive win for the home side two minutes from time, swivelling well to convert Nathaniel Clyne's cross.