Roma coach Rudi Garcia lamented his team's sloppiness in possession after their 2-1 loss to Inter on Saturday.
Mauro Icardi scored an 88th-minute winner at San Siro as Inter claimed a surprise win, moving into seventh and staying in the hunt to qualify for Europe.
Garcia felt Roma, who are third in Serie A, struggled with their build-up play and missed chances when they presented themselves.
"The strikers mustn't lose confidence, the problem was the way we built the play from the back. We misplaced too many passes between the goalkeeper and defence," he told a media conference.
"It was a good performance up front, especially [Victor] Ibarbo, who was unlucky to hit the post.
"We need to be more clinical in front of goal. We could have scored a second goal and maybe gone on to win it."
Radja Nainggolan had cancelled out Hernanes' 15th-minute opener, but Icardi restored Inter's lead late on.
Garcia urged his men to put the loss behind them with a clash against Sassuolo awaiting them on Wednesday.
"It was a good match tonight and the lads need to keep their heads up," he said.
"We play again in four days. We need to show the same desire and performance as tonight, but we'll need to be more efficient at the back and in front of goal against Sassuolo.
"Inter have good players and there's always a chance they'll score, but we could have done better defensively.
"We've not lost anything, though - we just need to win on Wednesday."