The Toon won 1-0 today thanks to Alexander Isak's early strike.
Saliba said afterwards: "We are all a bit sad because we wanted to win today. Unfortunately we didn't and we didn't play the game we wanted to play. We deserved to lose today I think.
"I think we didn't play how we wanted to play and they were good as well. It's OK, we are focused on the next week and it is not finished."
On the Newcastle goal, he said: "I think it's a good goal, a really good cross and good finishing but we can always do better. Today they scored early and we were not able to equalise.
"We have to stick together. Last season we had one period like and we need to stay together and have the confidence to get out. We all believe we will come back.
"I have to be better than my last game. I was not so good. I have to be back at my good level. After I will be good we will better but I have to work to get back to my best level."