Last Thursday's 30-27 loss to Zebre in the closing minutes brought an end to their play-off hopes for the season.
And while they are already confirmed to finish fifth in the table, Rees insists there is still plenty to play for in Saturday's match up with Connacht, most notably pride.
The Welsh region have enjoyed a strong record at home, recording seven league wins out of ten with their highest score being their 75-7 win over Treviso in round 14.
And after the difficulty of last week, Rees backed his side to put in a professional performance in their season finale.
"We have to hope for a positive reaction at the weekend," Rees told WalesOnline.
"It's remarkably difficult, but we are trying to be as professional as we can be, focusing on what we can do to make a difference against Connacht and where there might be opportunities.
"Defensively, too, we have to be better against a side who throw the ball about and have some threats on the field. If we're as naive as last weekend, and lack desperation, we'll get burned again.
"We've spoken about being in the Liberty Stadium and having some pride in our performance. We have to front up.
We've had some decent try-scoring exploits this season, especially at the Liberty, and we want to keep that endeavour because we think as a side there are areas where we can captivate and excite."
Follow us on Facebook, join the conversation on Twitter, sign up to our YouTubechannel for extensive match highlights and sign up for our newsletter for regular updates on the RaboDirect PRO12.
1st Floor Simmonscourt House
Ballsbridge, Dublin 4, Ireland