Real Madrid goalkeeper Thibaut Courtois blamed a "lack of intensity" for their 3-2 defeat to RB Leipzig on Tuesday as the Champions League holders missed the chance to seal top spot in Group F.
Josko Gvardiol headed home from close range in the 13th minute and Christopher Nkunku blasted in a second five minutes later, with Vinicius Junior pulling one back before half time.
Timo Werner struck what proved to be the winning goal from close range in the 81st minute, with Rodrygo pulling one back from the penalty spot for Madrid in stoppage time. It leaves Leipzig on nine points, one behind Group F leaders Madrid heading into the final round of fixtures.
"We went out there sleepily, not intense or aggressive enough, and you pay for that," Courtois told Movistar. "The coach warned us and still, we went out there poorly. They can't score two goals from corners. We made a lot of bad passes, had bad control, didn't win a lot of duels, lacked intensity. We didn't have a good game.
"A bad day can happen, there's been a lot of games in a short space of time, but what you can't lack is intensity. On the counter they are a very dangerous team."
The visitors were without Ballon d'Or winner Karim Benzema, as well as Luka Modric and Fede Valverde, for the clash in Germany. Ancelotti also rested Dani Carvajal and David Alaba.
Gvardiol broke the deadlock after 13 minutes when Courtois clawed away Andre Silva's header from a corner but the Croatian was on hand to nod in the rebound.
The Belgian goalkeeper had not managed to keep a clean sheet this season in La Liga, but had two in two Champions League appearances before this clash.
Courtois might have let in another moments later when Nkunku burst forward, rounded the onrushing goalkeeper outside the box, but then hit the side netting, albeit from a tight angle.
The French striker did not have to wait long for his goal, though. The 24-year-old doubled the lead shortly after when the ball broke to him in the box after a short corner routine, and he rifled in off the crossbar.
"We let in two goals from set-pieces and the game had a dynamic that they wanted, they are very good on the counter," Ancelotti told Movistar.
"I am not angry. It's a defeat, it annoys us, but it's a defeat that doesn't do us much damage. I can't criticise a team that has done very well until now. You learn more from defeats than from 10 wins a in a row."
Madrid roused themselves in the final minutes of the half, with Brazilian dynamic duo Rodrygo and Vinicius denied by Leipzig goalkeeper Janis Blaswich.
The stopper could do nothing to prevent Vinicius pulling a goal back in the 44th minute, heading home accurately from Marco Asensio's cross.
Leipzig substitute Werner wasted a good breakaway in the second half, while Vinicius should have equalised but poked the ball wide after Eden Hazard and Asensio combined well.
The Madrid forward was punished when Leipzig grabbed a third in the 80th minute, with Werner making amends by finishing from close range after a fine run and low cross by Mohamed Simakan.
Rodrygo added a late consolation from the spot after he was brought down but it was too late for Madrid to save their unbeaten record.
