Despite having failed to agree a new contract at St Andrew's and being unsure of his long term future, Larsson has been nothing but ultra professional in his approach so far.
And Watson, Blues' joint first-team coach, said Larsson had become more of a threat, too.
"Seb's endeavour should never be in question," he told the Birmingham Mail.
"But he's now getting in areas, the pay-off areas. Not middle and back, but middle to front and still giving us the work middle and back.
"We ask him to try and be productive in these areas because he's got great ability with the ball and being able to put balls in.
''We know that and Seb's been very good this pre-season."