"It was a bad game for Portugal," Silva said after the game (via Daily Mail).
"We managed to score the goal early but from then on we stopped playing. I cannot find a great explanation for this, words fail me.
"It was terrible, we have to do much better because we have a play-off in March and we will do our best to qualify. But at home, with 65,000 fans, we had to do much better.
"I apologise to the Portuguese (fans) who watched a game they shouldn't have watched. The plan was to try to have the ball, we were completely dominated by Serbia. With the quality of our players this is hardly admissible.
"I played a little bit limited, I tried to give my best until the moment came when I thought that another player would be in better conditions."