The Giallorossi were beaten 3-1 by Sampdoria, but Osvaldo had the opportunity to draw level when aiming a weak penalty into the arms of Sergio Romero.
“I wanted to take the responsibility of the penalty so I could help the team,” he told Roma Channel.
Francesco Totti had been the designated spot-kick taker, but Osvaldo insisted on taking it.
“I felt ready to take it. This has been a difficult week for everyone, I am very disappointed, but we have to look forward.
“Now everyone will turn their backs on me, but I go forward.”