According to the BBC's report, the decision came during the tournament semifinal against Novak Djokovic.
The account provided by the British network directly links Medvedev's exclusion from the China Open to the ball striking the spectator in the face.
The incident therefore occurred while Medvedev was facing Djokovic in the semifinal, according to information reported by BBC News.
In the BBC's report, the disciplinary consequence indicated for Medvedev is a default from the Chinese tournament after the shot reached the spectator in the face.
The news thus concerns a semifinal between Medvedev and Djokovic that ended, in terms of tournament participation, with Medvedev's default, according to BBC News.
The information available in the cited report is limited to the exclusion from the China Open, the ball striking the spectator, and the fact that the incident occurred in the semifinal against Djokovic.