The 25-year-old Austrian international has netted an astonishing 45 league goals in just 58 appearances for the Austrian Bundesliga outfit.
But he could soon be plying his trade in the Premier League, after revealing it has been his dream to play in the English top-flight from a young age.
"When I was about 12 years old, I was watching an English game on the television," he told the Daily Mail. "It was West Ham against Watford and everything about the English game, the pace, the crowd, the atmosphere, it was fantastic.
"I just turned to my father and said, ‘I’m going to play in England ’and now I want to make it happen."
And although his impressive goal haul has been played down by several pundits, criticising the quality of Austrian football, Janko - who has netted three times in seven outings for his country - remains confident he can be a success abroad.
"People will say the Austrian league is not so strong and, apart from Salzburg, Rapid and Austria Vienna, that may be the case, but you still have to put chances away and my record is comparable with the best," he said.
"Also, France, Italy and Serbia don’t have poor defences and I have scored against them. It shows I can compete against the best.
"I know clubs are interested and I know I can play in England. It may take a little time to adjust to the tempo but I can handle the physical side that everyone talks about.
"I have a strong left foot, I’m good with my right and, as you’d expect at 6ft 5ins, I’m good in the air.
"I just want to get to the Premier League and show what I can do. The club have been good enough to say I can go, but they have to find a replacement soon too, so it’s important all round that something is tied up soon.
"We need to start talking to the clubs. Tottenham are among my favourite clubs."
