Benitez rested several players as Chelsea lost 2-1 to the Saints, but after the Blues responded with a 1-0 win over Manchester United in the FA Cup, the former Liverpool boss has insisted that it isn't always possible to play his preferred starting lineup.
The 52-year-old told reporters: "I think that we proved against a team at the top of the table that we can compete against anyone, if we have the time and the players available.
"We have a lot of games, so you cannot do whatever you want to do. You sometimes have to try things in a different way."
The Stamford Bridge outfit face Rubin Kazan on Thursday in what will be their third fixture in six days.