Roma coach Claudio Ranieri admitted his side struggled to cope with Inter Milan's physicality in their 5-3 defeat at the San Siro on Sunday.
Leonardo's revitalised Inter were too powerful for Roma as they moved within five points of the Serie A summit with a game in hand on top two AC Milan and Napoli.
"We have to compliment Inter," Ranieri said. "This is a physical Inter and you can only beat them if you play in the same way.
"When you come up against a team like this one there are differences.
"Inter have players that can make the difference and their bench players have always proved crucial to getting results.
"We also have some of those players but they are unavailable."
Roma, who were reduced to 10 men in the 63rd minute following Nicolas Burdisso's sending off, did show plenty of spirit, however.
Trailing 4-1 with 19 minutes remaining, they scored twice to cut the deficit before Inter's Esteban Cambiasso killed the game off a minute from time.
"I thought my players did really well," Ranieri said. "We never stopped believing and we reacted showing great character."
The result dropped Roma to seventh in the standings, 10 points adrift of top spot, but former Chelsea boss Ranieri remains confident they can still challenge for the Scudetto.
"It's not easy when you have to cut a big gap because not only do we depend on our results but on the outcome of other games," Ranieri said.
"But we have to keep fighting and give our all until the last second.
"There are still many games left to play.
"We have done good things this season and I'm sure we will continue to do well."