The UEFA Champions League finalists came from behind twice to draw 2-2 at home to Valencia on Sunday, with Cristiano Ronaldo scoring a late equaliser.
The draw came a day after Barcelona were held by Getafe and, just hours earlier, La Liga leaders Atletico Madrid had suffered a 2-0 loss at Levante.
"We missed a chance but it is not so big because the draw is OK," the Italian told a news conference.
"If we would have won tonight, Atletico would have had to win at Barcelona. As we drew, for Atletico the draw in Barcelona is enough, but we have to win the next two games.
"We should be so focused on it. For Atletico the draw in Barcelona now is fine. So, we missed a chance but not so big."
Parejo's neat finish on 65 minutes restored the visitors' lead, but Ronaldo levelled in additional time with a clever back-heel.
Ancelotti believes his team's efforts in Europe have made it tough for them to be ready physically.
"I think basically the problem has been physically," he said.
"The same problem has happened as well to Atletico de Madrid and Chelsea.
"When you play a semi-final of the Champions League, it's normal the following Sunday if you cannot give as much intensity as usual. I think we paid for that."
Ancelotti talked up the importance of Ronaldo's equaliser, saying a loss would have ended Real's title chances.
"That was very important for us, because if we'd have lost, we'd also have lost La Liga," he said.
"The goal from Cristiano keeps us with options."
