... returned the ball, mid-rally, to the right base-line but the ball was called out by the linesperson.
Williams challenged and HawkEye system showed the ball to be IN.
However, the point was not awarded to Williams - despite HawkEye showing that Williams' shot was in - instead, the umpire ordered the point to be replayed.
Why??
Surely Williams was owed the point immediately? As HawkEye showed the shot to be in. I don't get why sometimes it's overruled and sometimes replayed