Dean Ashton had not found the net in his 10 previous matches but rediscovered his goalscoring touch with a vengeance, hitting a hat-trick in the space of 36 minutes to sink managerless Saints.
Southampton, in the caretaker reign of Dave Bassett, went ahead after nine minutes through Djamel Belmadi. Then Ashton took over.
His first goal came from a header on the half-hour, his next two came from Youssef Safri crosses, again heading in six minutes into the second half and forcing in the ball in the 66th minute for his 10th goal of the season.
His goals will have alerted Premiership clubs with the transfer window set to open. "There is every chance that this will increase the interest in Dean," the Norwich manager, Nigel Worthington, said. "But unless there is a very substantial offer on the table he won't be going anywhere."Reuse content