The 19-year-old confirmed as the youngest season-ending world number one.
Rafael Nadal is out of the ATP Finals after Casper Ruud's victory over Taylor Fritz. Will the 22-time Grand Slam champion ever win the season-ending event?
With the Norwegian already through to the semifinals, will FAA or Fritz join him come Thursday in Turin?
Also in this week's mailbag: why aren't there more female coaches on the WTA circuit?