Rees had spoken all week of the need to turn the Parc-y-Scarlets into a fortress and the Wales hooker was clearly hugely disappointed to have seen his side slip to a first home defeat of the season.
But while losing to the Ospreys is a feeling that Rees himself described as 'the worst in the world', the Lions star still believes the Scarlets can start their Heineken Cup campaign with plenty of confidence.
"We need to be winning home games, we wanted that so much and the boys are very disappointed," said Rees, after scores from Richard Fussell and Alun Wyn Jones steered the Ospreys to victory.
"We let in two soft tries in the second half that probably cost us the match and we're not taking that lightly.
"Our home crowd were outstanding and that's what derbies are all about. That game was really up there in terms of atmosphere.
"Despite being hugely disappointed, there are positives to take out - that was a tough game and will be good for us going into Europe.
"The boys are ready to kick-off the Heineken Cup now and Saturday's game here will be very physical - we'll have to muscle up.
"Perpignan are a quality side and we hope we'll have another good crowd behind us again to help us fight hard in our opening game in Europe."
The Scarlets welcome French Championship runners up Perpignan to west Wales this weekend, before travelling to Welford Road to face English Champions Leicester Tigers a week later.
And while those two fixtures would present a massive challenge for any side, Davies is convinced Saturday's defeat won't affect his team's self belief ahead of their continental campaign.
"This was a game we felt we could have won and we are frustrated it didn't come our way," explained Davies, after a 73rd-minute drop goal from Dan Biggar gave the Ospreys victory.
"But I was really proud of my players. They have shown how far they have progressed and we can take a lot from that going into Europe.
"This group is going to get stronger and stronger and we are definitely going in the right direction.
"Now we have to come back next week and focus on a big European opening game for us on Saturday."