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.
Without their electric attackers at full strength, Ancelotti was pleased his side still took it up to the German champions.
"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."
After taking the lead in the 19th minute via Karim Benzema, Ancelotti said his side controlled proceedings in the second half at the Bernabeu.
"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."
And without his stars at their peak, Ancelotti said team work was key.
"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."
On the second leg at the Allianz Arena, a place Real have not won at in five attempts, Ancelotti said he was optimistic of reaching the Champions League final.
"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."
