Goals from Gareth Bale and Clint Dempsey put Spurs two goals ahead of Southampton after 45 minutes.
Gareth Bale has scored against his former club to help Tottenham Hotspur earn a two-goal advantage over Southampton at the interval.
Spurs dominated from the outset and took the lead on 17 minutes when Bale headed home Jermaine Defoe's cross.
Bale opted for a muted celebration but nearly had a hand in a second Spurs goal just two minutes later when he drove a fierce cross agonisingly wide.
Defoe helped create Tottenham's second goal before the break when he played Aaron Lennon into a dangerous position.
His scuffed shot was stopped on the line by Jose Fonte but his clearance fell to Clint Dempsey, who made no mistake from close range to put Spurs firmly in control at St Mary's.
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