Coach Rudi Garcia said Roma's Serie A title challenge is virtually over after a 1-0 defeat to Napoli left his side 14 points adrift of leaders Juventus.
Roma have a game in hand after a recent fixture with Parma was rained off.
But even if Roma claim those three points, Garcia believes even an 11-point gap to the champions would be nearly impossible to close in the remaining 11 games.
A Roma defeat to Parma could also bring Napoli to within three points and in sight of the second and last automatic qualifying place for the Champions League.
Garcia told Sky Sport Italia: "Now, the gap (on Juventus) is fairly significant. We just have to keep on going and stay focused on reinforcing second place."
Roma travelled to the San Paolo hoping to reduce the arrears on Juventus after Antonio Conte's side had stretched their lead to 14 points with an earlier 1-0 win over fourth-placed Fiorentina.
However Roma missed a host of chances and were punished in the 81st minute when Jose Callejon rose to meet Faouzi Ghoulam's cross from deep on the left to beat Roma 'keeper Morgan De Sanctis with a precision header.