Most confusing tournament ever!
"Right, I'm trying to work out how Del Potro can win this third set and take Murray through with him - basically, the Brit's hopes seem to rely on Federer winning but more on that to follow. Back on court, Del Potro gets the deciding set under way with a confident hold."
"It seems the only way Del Potro can win and take Murray through with him is if he wins this set on a tie-break. Anyway, nobody seems to know for sure so we may as well concentrate on the tennis and worry about that later. Del Potro holds out with ease too."
"OK. I'm told that, if Federer gets to four games in this set, he and Murray are through - regardless of whether Del Potro goes on to win the match. Del Potro holds - sorry for the lack of description but I'm spending more time on my calculator than I am with my keyboard."