Louis van Gaal wants Manchester United to develop a ruthless streak.
United are on a roll after winning four straight games for the first time in almost 12 months and can leapfrog the Saints into third place with another triumph over Ronald Koeman's men.
But despite the purple patch, Van Gaal insists United still haven't found their killer instinct and he added: "It is always that we can improve. It is never 100 per cent all right. Never.
"This team is capable of killing off opponents. We have to dominate more.
"Against Hull we dominated and that is why I was so pleased. We could have scored more goals also.
"But 3-0 is a very good result against a very defensive team. I would always like to play like that.
"But that is not possible and I know in advance that we will strive for that moment."
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