Saints entered the 2017-18 campaign full of positivity after winning all four of their pre-season engagements.
However, they found it hard to continue that momentum into last Saturday's Premiership clash with European champions Saracens at Twickenham.
Northampton conceded 55 points, the second highest total in their Premiership history, and although they managed to put 22 on the board it was a humbling afternoon.
Brookes says the squad are capable of bouncing back this weekend when they host fierce rivals Leicester Tigers and insists they owe it to their fans.
"We owe the supporters a performance, and we owe ourselves a performance," Brookes told Northampton's official website.
"No one was proud of how we played so it's time to set it right.
"It was completely away from how we want to play the game, in attack, in defence, everything we talk about. We didn't bring it, so there was a massive sense of disappointment among the lads in the club this week.
"Monday, Tuesday and Wednesday were pretty brutal and intense in training and everybody's out to show what we're about, and not the display that we showed last Saturday.
"No one was happy about what happened last weekend, coaches, players or fans, but we have to draw a line under it, learn from the mistakes that we made and try to rectify them for this weekend."