"Warren and I watched him a couple of times over there and, when you see a player like him with his physical ability at a young age and ability with a football, it was a no-brainer really.
"We were just lucky with the timing as we were there and he was playing against us and was available to get. Although it was a bit of hard work to do it, we've got him and it's just a no-brainer because he has fantastic potential."
Janko earned his first caps for Switzerland's Under-19s earlier this month, helping them to beat Romania 3-2 and then 4-0 in back-to-back games during the international break. Playing as a right wing-back in the first match, he set up a goal for team-mate Shani Tarashaj.
"Saidy played against us in the Blue Stars tournament in Switzerland and stood out straight away."
- Nicky Butt, United Under-19s coach