Is it less effective if you start your new cycle with birth control pills one day later ?

i usually start my new cycle on sundays , but due to a stomach virus i took it monday instead , will that cause it to be less effective ?Is it less effective if you start your new cycle with birth control pills one day later ?
The most important pills to take on time are the first and last active pills in a pack. Use condoms as backup birth control for a week, and you should be fine.