Medvedev's first career victory over the 20-times Grand Slam champion sent him through to a final showdown against Dominic Thiem who earlier beat Novak Djokovic in another titanic clash.
The 24-year-old Medvedev reached the semi-finals as the only player to post a 100% record in his group, including a superb defeat of Djokovic.
Thiem will attempt to go one better than last year when he lost to Stefanos Tsitsipas in the final.
