Madrid, who lead the LaLiga table after one defeat in 24 league matches, head to the Bundesliga side with plenty of injury problems. Midfielder Jude Bellingham is the latest blow after being diagnosed with a sprain in his left ankle.
The 20-year-old England international has had a stunning season since his 103-million-euro move to the Santiago Bernabeu from Borussia Dortmund in June and has scored four goals in five Champions League matches.
Goalkeeper Thibaut Courtois and defenders Eder Militao and David Alaba are long-term absentees with knee ligament injuries.
But Ancelotti is confident Real can overcome the setbacks.
"I never think about the ones that aren't here," he told reporters on Monday. "There's no Bellingham, but without him, we won four out of four. These injuries have been an opportunity to be more motivated. We can do well against Leipzig.
"We're on a good run, motivated, in a competition that we like a lot ... "
The German side are in fifth place in the Bundesliga.
"They are a strong opponent, they play intensely and with quality up front. We will play a complete game, especially defensively," Ancelotti added.
"I see a solid (Real) team, serious, motivated, with a good atmosphere, nobody complains, everyone contributes...
"Everything is going well so far, despite all the difficulties we've had... It was thanks to the character of the players," he added.
Ancelotti was also asked about Real stalwart Toni Kroos' future at the club, as the 34-year-old German midfielder's contract expires in June.
"Whatever he decides, you have to respect it. One, I think, has to leave it at the top. This year he can be, or next year, I don't know, because his performance has always been good," said the Italian.
