Real beat title-holders Bayern Munich 1-0 in the first leg of their UEFA Champions League semi-final in Madrid on Wednesday, with Portuguese attacker Ronaldo playing at less than 100 per cent and Welshman Bale limited to a substitute appearance due to suffering from the flu recently.
Bale replaced Ronaldo on 73 minutes.
"We're more comfortable defending with a 4-4-2, against teams that have so much possession. Without the ball, it's better to defend that way and we've done well," Ancelotti said.
"Without Bale (starting) and with Cristiano at 50 per cent, it's not easy to do this well. Cristiano was sure enough he could play and he's done well."
"We were timid at the start and we had some difficulties," Ancelotti said.
"In the second half we had more control of the game. We had to defend, but we've also had some very good counter-attacks."
"Working together as a unit was fundamental," he said.
"(Fabio) Coentrao had help from Isco and (Daniel) Carvajal from (Angel) Di Maria. In a semi-final, you need that."
"The game there will be very difficult and we'll have to play it with the same desire and confidence, as we've played today," the Italian said.
"You never know what might happen, but I'm confident."
