Ancelotti opted to rest Gareth Bale for the fixture ahead of Tuesday's derby clash with Atletico Madrid in the UEFA Champions League quarter-finals, but allowed Ronaldo to play the full 90 minutes.
The Portuguese opened the scoring in the 21st minute and, with Real going in 2-0 up at the interval, Ancelotti might have been forgiven for thinking about replacing the attacker.
"Because he recovered well from Wednesday's game [at Rayo Vallecano] I preferred to remove other more tired players, such as [Sergio] Ramos, Marcelo and [Luka] Modric," he said.
"He [Ronaldo] is really enjoying the game because the team is playing with more speed and that gives him more freedom in front of goal.
"For Tuesday, all players are available. We put in a lot of effort but everything went well."
Real lost 4-0 on their last visit to local rivals Atleti back in February, a fact not lost on Ancelotti.
"It's a motivation," he added. "But it's a different game, a difficult game.
"We're motivated and we will give our best.".
