It was a decent warm-up for Barca, who extended their lead at the summit to 14 points, but Roura knows their next fixture will be a different prospect.
"We're very excited to play the match and we're eager to compete," he said on the club's official website.
"We will give everything we have to fight back until the referee blows the final whistle.
"Logically, we have to attack. However, we shouldn't confuse our desire to fight back with haste, we need to find the necessary balance."
Roura, in temporary charge of the Catalans while Tito Vilanova undergoes cancer treatment, has not decided his starting line-up for the clash with the Italian giants.
However, he knows how he wants to approach the clash, adding: "We're fairly certain on how Milan will play and how we want to play. Afterward, we'll see how it all plays out."