Lazio boss Edy Reja was unhappy with AS Roma captain Francesco Totti after last night's derby defeat.
Totti hit a brace, while Lazio finished the encounter with nine men.
Reja said: "The derby is a match that really is felt deeply in the city. It was a balanced game, then Roma found the breakthrough with the free kick. I felt Nando Muslera's vision was impaired during the incident.
"Totti was also involved in other incidents and we fell for his provocation. These tricks can happen and it was our fault for being excessively tense and falling for it.
"When you are in the lead, you try to waste time and we know Totti is very good at that sort of thing. He is experienced and knows how to slow down the game.
"It's a shame, as I was missing three players, but the season does not end today. We were lacking something in terms of determination and, when you lose three or four derby games in a row, you need to have more belief."
