United won the Premier League opener 1-0 thanks to Joshua Zirkzee's 87th minute winner.
Silva later said: "It is really tough for us to lose this game the way we lost. The game had different moments, we started really well, I think the first two dangerous moments were from ourselves. The first one we should have scored, a really dangerous attack from us.
"After 20 minutes good reaction from Man Utd. We adjusted at half-time and the second half was much better in my opinion. We had our chances. When you play against Manchester United...there were moments and we had to punish them.
"We had so many moments and we were punished at the end of the game. It was a crazy game and we did not play our own game. It was an emotional game, we tried to rush many, many times.
"We did not get the points I thought we deserved.
"Of course when you have two against one you should at least finalise the action and put your teammates in the right action. But it was not just that one, we had other really good moments and should have scored.
"We have to keep the emotional control in these types of games. We know they are strong and want to play this type of game. It's always their strength when the game is broken and the space is there. We should have kept the balance and emotional control.
"But it was a good answer from the team overall, we just didn't get the points I think we should have.
"It was a tough summer, when you lose five players - four of them starting players. But I knew the players were good enough to play in this way."