Ancelotti worried about World Cup impact on Madrid's Champions League defense

Carlo Ancelotti believes the biggest unknown surrounding Real Madrid's potential Champions League defense is the potential physical condition of his players when they return from the World Cup.

Madrid begin their quest for a 15th European Cup on Tuesday by meeting Scottish champions Celtic.

The group stage is condensed this season due to the World Cup being moved from its usual summer slot in the Northern Hemisphere to November due to the extreme heat in Qatar.

Teams involved in the group stage will play six games in less than two months, with the battle for a place in the last 16 ending on November 2.

In addition to national commitments, this results in a busy list of matches. Yet Ancelotti is less concerned about the effects of the calendar than the potential cost to his side of playing in a mid-season World Cup.

"Until the World Cup, I think we won't have any problems," Ancelotti said of the unusually heavy fixture list.

"The players are prepared and motivated. The question is how the World Cup players will come back. That cannot be known."

Madrid are not seen as Champions League favorites despite their remarkable run last season. Los Blancos delivered thrilling comebacks against Paris Saint-Germain, Chelsea and Manchester City before beating Liverpool 1-0 in the final.

City is the favorite of bookmakers ahead of PSG, Liverpool and Bayern Munich. Ancelotti, however, is happy that his side are not in the top four in this sense.

"I'm not surprised. I see that as a good sign," he added. "I think last year we had even less probability in the stats. So we got better.

"What happened last year will happen. We will compete until the end and hopefully we will make it to the final."

Ancelotti's side are the heavy favorites to win Group F, however, which also includes RB Leipzig and Shakhtar Donetsk, as well as Celtic.

But Ancelotti pointed to Madrid's surprise home loss to Sheriff Tiraspol in last season's group stage when asked about their seemingly easy draw.

"It's not an easy group because we know the teams very well," said Ancelotti. “Celtic are doing very well, we have to respect them, like Leipzig and Shakhtar.

"In the group stage there are surprises, especially in the first half. We have quite vivid memories of last season with Sherriff at home. We respect the group and I think it will be a group equal.”