Real Madrid fought back from two goals down as Vinicius Jr grabbed a hat-trick in a thrilling 5-2 win over visitors Borussia Dortmund in the UEFA Champions League on Tuesday.
In a rematch of last-season's final, Dortmund lit up the game with a two-goal blitz around the half-hour mark from Donyell Malen and Jamie Gittens to silence the Bernabeu crowd.
However, the champions were livelier after the break and broke Dortmund's resistance with Antonio Ruediger's header on the hour before Vinicius equalised with a close-range strike.
Lucas Vazquez put Real ahead in the 83rd with an unstoppable strike after a counter-attack and Vinicius, with two pieces of individual Br azilian brilliance, wrapped up the win to leave his side level with Dortmund on six points from three games.
Still figuring out the ideal lineup and formation for a Real midfield missing the creative talent of Toni Kroos, who retired at the end of last season, Ancelotti reverted to his usual 4-3-3 after trying out a system with three center-backs in an unconvincing 2-1 win over Celta Vigo in LaLiga at the weekend.
However, after a promising first half hour in which Real looked solid at the back and in control of the match, Dortmund took advantage of a lack of concentration by the home defense to score twice in the space of four minutes.
Real looked as stunned as the home fans, anxiously missing several chances, and were often exposed by counter-attacks, with goalkeeper Thibaut Courtois making brilliant saves to deny efforts from Gittens and Julian Brandt before the break.
Elsewhere, Arsenal needed an own goal to seal a scrappy 1-0 win over Shakhtar Donetsk as they made it two wins out of three in the Champions League to soften the blow of their first domestic league defeat of the season at the weekend.
The hosts missed a penalty in the second half and squandered a number of decent chances, but the reality was they never found top gear and had to withstand some late pressure.
Arsenal, who were beaten 2-0 by Bournemouth in the Premier League on Saturday, made a fast start with Br azilians Gabriel Martinelli and Gabriel Jesus both having good opportunities before a fortunate opener in the 29th minute.
A low shot from Martinelli rebounded off the post and off the back of Shakhtar keeper Dmytro Riznyk for what turned out to be the only goal of the game.
Arsenal would have doubled their advantage before halftime were it not for Shakhtar captain Mykola Matviyenko who hooked the ball off the line to prevent a diving Kai Havertz nodding in.
Leandro Trossard also missed a second-half penalty awarded by video assistant referee (VAR) following a handball in the box.
Shakhtar, who are yet to win in the Champions League this season, put more pressure on Arsenal after the interval and went close to equalising when substitute Pedrinho had a long-range effort superbly saved by Arsenal keeper David Raya in stoppage time.
Victory lifts Arsenal provisionally into the top four of the new 36-team league phase before Wednesday's fixtures with their next match away at Inter Milan. Shakhtar will seek to bounce back in their next match at home to Swiss side Young Boys.
Arsenal will be relieved to have sealed the win but without key playmakers Bukayo Saka and captain Martin Odegaard who were missing through injury, were well off their fluent best.
Arteta, whose side have also suffered from three domestic league red cards this season, substituted defender Ben White at halftime after he had picked up a yellow card.
Riccardo Calafiori was also taken off with 20 minutes to go after the Italian landed awkwardly following a challenge.
In other fixtures, Juventus suffered a shock defeat 1-0 by VfB Stuttgart, PSG were tied 1-1 by PSV, Monaco and AC Milan enjoyed big wins over Crvena zvezda 5-1, and Club Brugge 3-1, respectively. Meanwhile, Girona, Aston Villa, and Sporting all cliched wins of 2-0, over Slovan Bratislava, Bologna, and SK Sturm Graz, respectively.