The band kick off 17 nights across the UK and Ireland at St Mary's Stadium.
Henry Nowak, 18, was initially treated as a suspect by police despite suffering five stab wounds.
Flags were placed on street furniture as part of a movement known as Operation Raise the Colours.
Take That fans have been sharing stories as the band prepares to start their tour in Southampton
First-year university student Henry Nowak was killed as he walked back from a night out in Southampton.
Southampton must be "very careful" over their debts and fiscal position, says football finance expert Kieran Maguire.
Take That are kicking off a reboot of their Circus Live tour at Southampton's St Mary's Stadium.
Henry Nowak's alleged killer has claimed during his trial that he was acting in self-defence.
Southampton FC and Royal Antwerp announce the death of former academy player Victor Udoh at the age of 21.
