The City Ground club were beaten 3-1 at home by Newcastle United, despite being 1-0 up at half-time.
While they are still in a top ten position, Santo knows that his team can quickly slip down the table unless they get back to basics.
“I wouldn’t say it was frustrating. OK, we lost the game but when you lose and when you win there is always a lesson to learn. Today we must learn an important lesson,” said the Portuguese post-game.
“It is easy to see we’ve been punished by the way that we’ve been punishing other teams. That’s a reflection to be made on the game.
“I cannot say it’s a bad performance, honestly. We have to give credit to Newcastle because they are a good team and they were able to control us. They were able to take advantage of some decisions we made when we were rushing our decisions, and they punished us on the counterattack. They have pace and they have quality, and they were lethal with the chances they had.
“I always believe every game gives you a chance to improve and a lesson to take. Today, I think our improvement should be on the momentum of our decisions. We rushed our decisions and were not able to keep the ball enough time to make Newcastle players drop. When you attack and you defend and the team is organized, you know they are going to come. It is something we have to address.
“Even though we lost the game today, I am very pleased. All of us at Forest should be proud of our players and the way we have been working together.”