Gilles just rolled his left ankle
and forfeited the match vs Richie immediately.
It doesn't look very bad -- he didn't fall over or completely turned the ankle -- but still worrisome. 2-3 days rest should be fine.
It's a pity he's been playing well so far despite being down 1 set.
Updated (Or it looks more serious than I thought):
Simon had to be carried off the court in Kooyong. On net approach landed on the outside of right ankle when he split-stepped.