In Wimbledon 2018, the first semi-final (Anderson vs Isner) of gentlemen's singles went on for 6 hours and 35 minutes on Friday, 13 Jul 2018. This caused the start of the second semi-final (Nadal vs Djokovic) to be delayed well beyond its scheduled start time. Due to the curfew at 23:00, play was suspended after the third set, and it was decided to resume the game next day (Saturday) at 13:00.
The final is scheduled to be played on Sunday. If the second semi-final match doesn't finish on Saturday (due to its final set also going on for a long time, and perhaps "assisted" by rains, bad light, or other interruptions), then what happens to the final?
Moreover, if the semi-final is completed on Sunday, will the final be started soon after (thus putting the exhausted winner of the just concluded semi-final at a massive disadvantage)? What are the official rules of the Wimbledon tournament regarding this situation?