I tried to post in the question how to skip a level, but it said the thread was too old. Hopefully a moderator can tack this on to that old thread.

To earn the option to skip a level in single player, you need to surrender/bust a consecutive number of times. If the skip feature triggers, you will see an additional prompt before the usual history/try again pop up asking if you would like to skip the level you surrender/got defeated in.

Cheers