The Toffees boss named a side showing 11 changes for Tuesday's trip to the south coast and subsequently saw them slip to a 4-1 defeat.
That decision has since been questioned but Lampard believes he had little choice but to change things up given the demands placed on his players.
And, when asked if he had any regrets over his choice of team, he replied: "We lost the game [but] in terms of selection, no, because we have to use the squad.
"We haven't got, probably at this point, a squad to compete. I think we showed that, through league, through cup, when you’ve got three games in a week, what the Carabao Cup would have meant to us.
"We wanted to win the game and the onus was on the players who played to win the game, and it didn’t happen, it’s done now, we move on to tomorrow.
Everton fans were dismayed to be denied a run in a competition that arguably represents their best chance of ending a 27-year wait for silverware.
Asked about their reaction, Lampard added: "I understand that, every fan should have an opinion, it might be what Arsenal fans are saying, what Tottenham fans are saying, what West Ham fans are saying or Liverpool fans nearly might have said.
“So this is the job that we do and when we work with 20 plus players that are playing for Everton, representing Everton, training every day, some training well, knocking on your door, and you might have to rely on them in the season, or they state a case to become a regular in the team, you have to have a moment to show that.
"Tuesday was a moment to show that, and on the night, to be honest, not enough showed that and that’s for me to take stock and for those players to know next time they get their opportunity, whenever that is, they better be of the level.
"So it was an exercise in those terms, not that I used it as an exercise. It’s a game that, in my opinion, we should go there and get a result. Of course we made mistakes, we had chances, clear chances, that we missed and those things are always going to affect a game.”