Roma stunned Inter 3-1 at the San Siro.
Strama said: "I didn't like the drop in intensity after we went 2-1 down. In that moment we had the game in hand and started the second half really well, but Pablo Osvaldo's goal on that great Francesco Totti assist found us unprepared.
"We didn't do well in that phase of the match and I think it was more of a psychological problem than a football one.
"We cannot concede goals like that on home turf and then feel such a heavy psychological blowback. We have a lot to work on, because we are a new team and so must quickly turn the page."