What if the semi-finals are not completed before the scheduled start of the final?

Question

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?

Answer 1

Before the Centre Court roof, this was more common because if there were a lot of rain delays it was very difficult to make up the time - though even then it was unusual.

Wimbledon will not schedule two matches for the same player in the same event on the same day. If that means that the finals scheduled for Sunday have to move back to the third Monday, then the tournament will be extended by a day.

This is known as a "People's Monday"; because no tickets will have been sold in advance the stands will be filled entirely with people who were waiting in the ticket queue outside the complex. (Similarly, if rain delays in the first week mean that they need to play on the middle Sunday to catch up, this is a "People's Sunday".)

A famous example (at least for Brits) is the 2001 men's singles final. Rain delays meant that Tim Henman and Goran Ivanišević's semi-final did not finish until the Sunday, which meant that the final between Ivanišević and Rafter could not be held until the Monday. There's a description of that final here and here.