Spurs take on Bournemouth this weekend and the Belgian is keen to ensure that mistakes aren't repeated.
Spurs travelled to Belgium with high hopes of taking a big step towards reaching the latter stages of the Europa League, but a disappointing display saw them beaten 2-1 despite taking an early lead through a Christian Eriksen goal.
It was a highly frustrating loss for Mauricio Pochettino’s side, whose lack of focus saw them concede two poor goals and surrender their lead.
And Dembele says the failings on show in that contest cannot be allowed to be repeated.
"Anderlecht woke us up," he told tottenhamhotspur.com.
"Against teams like Bournemouth we know it’s going to be difficult. We shouldn’t underestimate any team like we did against Anderlecht.”
Spurs travel to newly promoted Bournemouth this weekend looking to return to winning ways after a frustrating draw with Liverpool last time out.
Bournemouth will also be up for the game as they seek to prove their Premier League worth following a highly demoralising 6-1 defeat to Manchester City.
It is unlikely to be an easy game for either side, and Dembele says his team must be aware of that fact, but has backed them to be okay if they take their chances when they come.
"Teams like Bournemouth who have just come up always want to fight that much more,” he added.
“That’s something we need to be aware of and understand how tough it’s going to be. We need to stick to our game plan and play the way we want to play and if we take our chances then we will be okay in the end."