Luciano Spalletti was left to rue Francesco Totti's missed penalty following Roma's 1-1 draw with Olympiakos in the UEFA Champions League.
Totti made amends with a well taken equaliser in the second half as Roma dominated their opponents, but the dropped points mean the Italian side must now wait until their next game at least before clinching their place in the second round.
"There are a few regrets, as we could have rested some players in the final two rounds," sighed Spalletti.
"Olympiakos were within our grasp and we were a lot better in the second half, but couldn't make the most of our chances.
"We didn't use the freedom Olympiakos allowed us on the flanks. What we were lacking was the midfield unity and sharpness to win the ball back quickly and spread the play. That gave the Greeks the midfield in the first half."
Spalletti also conceded that Totti may now have to stand down from spot-kick duty.
"Every player has moments when things don't quite go his way. Someone of Totti's character and quality, as you all saw in the World Cup, knows when he's ready," he explained.
"We'd have to ask him about this issue and decide together."
Roma can clinch qualification to the last 16 with victory over Shakhtar Donetsk in their next Group D game, but Spalletti is not taking anything for granted, despite their 4-0 win over the Ukrainians last time out.
"It will certainly be a difficult game. Although we won 4-0 last time, the result really didn't show the whole story, as they played a brilliant first half and put us under a lot of pressure," he recalled.
"Their heads dropped after the second goal and we took advantage, but it will be a very tough match."