The Toffees were dumped out of the Carabao Cup as they suffered an embarrassing 4-1 loss to the Cherries in the third round of the competition.
The Everton boss, via beIN Sport, said: “The players who haven't had my minutes get opportunities, as Gary [O'Neil, Bournemouth manager] did with their team. They fell below the standard, for sure.
“The league is hugely important but every competition, when you put the Everton shirt on, is important. Also, when you work daily with the players in the squad that are not playing sometimes knock on your door, they train well, some of them, and deserve an opportunity.
“These, as Everton, are an opportunity to play these players and may need them and refer to them and they may be able to get themselves in the team at some point. It helps you in the league and any cup.
“For them, it was an opportunity to play and do well and clearly, I learnt a lot from it. Maybe some stuff I already knew, maybe some more stuff I already knew so that was it.”
Everton went into half-time a goal behind courtesy of Jamal Lowe's deflected effort.
But they were architects of their own downfall in the second period, with Mason Holgate and Nathan Patterson making errors for the Cherries' second and fourth goals.
Lampard rued 'calamitous' defending as Bournemouth doubled their lead two minutes after the interval - and knew his side was given a mountain to climb.
He made a triple substitution, with Demarai Gray coming off the bench to reduce the deficit before the home side stretched clear.
Asked if he was optimistic after introducing Gray, Alex Iwobi and Dwight McNeil, Lampard replied: “Optimistic because when you send on those players, you know there's an impact in all three. They were options from the bench hopefully needed or didn't need for different reasons.
“They did impact it, it's an uphill battle. The first half was all ours, they score a deflection and we miss two glorious chances. So, at that point, when you make a calamitous second goal to gift them a goal, the game becomes very difficult no matter who you're bringing on. Really poor and we haven't been poor so it tells me a lot of things.”