david campanale, bbc news. draw at the us open. two teenagers are into the semi finals. the 19—year—old canadian leyla fernandez, who played an extraordinary match to win through to the last four on tuesday. and now the british sensation emma radukanu who is still only 18 — and is the first woman in us open history to go through qualifying all the way to the semifinals — which is a pretty remarkable achievement. here's david law, the bbc tennis commentator. it suddenly feels possible now. the fact that the two of them are in the semifinals, and the manner in which they are plain to have got there, as well. you mentioned that layla fernandez, the 19—year—old from canada who's beaten last year's champion, naomi osaka, she's beaten angelique kerber, the former champion, and now elina svitolina, one of the top five players in the world. but, perhaps even more remarkably is the way that emma raducanu, the british player who had not even played this tournament before this year, is going through all the qualifying rou