Teenagers Leylah Fernandez, Emma Raducanu and Carlos Alcaraz are lighting up the US Open

Fears the US Open might lack some fizz without injured superstars Serena Williams, Roger Federer and Rafael Nadal have been unfounded.

Instead, the tournament has provided a window into what the tour will look like when they hang up their racquets.

A teenage trio has flourished at Flushing…