We started superbly in Brussels on Thursday night, went ahead but then missed chances to put the issue beyond doubt and allowed Anderlecht back into the game.
The Belgian side didn't need a second invitation and went on to win 2-1 in Europa League Group J.
Mauricio Pochettino spoke afterwards about a 'lack of focus' and the disappointment of the travelling squad suggests it's unlikely to happen again.
"Anderlecht woke us up," said Mousa. "Against teams like Bournemouth we know it’s going to be difficult.
"We shouldn’t underestimate any team like we did against Anderlecht.
"Teams like Bournemouth who have just come up always want to fight that much more so 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."
We go to Bournemouth on a run of eight unbeaten matches in the Premier League stretching back to the opening day. Bournemouth, promoted as champions last term, are currently 17th having won one of their last six.