MADRID -- "Our crown, our trophy," read the banner, held up by fans behind the Santiago Bernabeu's south goal before kickoff.

Real Madrid are the reigning European champions, the 15-time UEFA Champions League winners, and, of course, the comeback kings, as they showed once again in this unpredictable, wildly entertaining 5-2 win over Borussia Dortmund.

This is a strange Madrid team, full of elite players, but often malfunctioning as a unit. They flirted with embarrassment against Dortmund before they decided to play the hits, and turn the game around, roared on by the Bernabeu crowd.

In the first half, they were poor: fragile in defence, non-existent in midfield and hesitant in attack. In the second half, they looked like an unstoppable force of nature, led by the irrepressible Vinícius Júnior. The Brazilian scored a hat trick, in what's a contender for his career-best performance to date. This was Ballon d'Or-worthy. By the end of this month, he might have one.

In the old Champions League format, Madrid never failed to qualify from the group stage, ever. Here, they faced a real risk of starting the new league phase with two defeats in three games. Their 1-0 loss at Lille on matchday two could have been dismissed as an anomaly -- Madrid created nine chances there, with an xG (expected goals) of 2.18, but lost 1-0 -- but Tuesday's first-half performance, going 2-0 down to Dortmund and conceding twice in four minutes, made it look more like a trend.

Madrid have not been playing well this season, but they've still been winning games, and are unbeaten in LaLiga. There was optimism, excitement and expectation ahead of kickoff here, the feeling of a big European tie, and a repeat of last season's Wembley final. The atmosphere generated by Dortmund's thousands of travelling fans helped. Midway through the first half, their coordinated, mass bouncing had the desks in the Bernabeu press box moving gently up and down, all the way across the stadium. On the pitch, their team gave them every reason to jump up and down.

Donyell Malen's opening goal after 31 minutes was well worked, a team move that ended with Malen on the ball, in space, in front of goalkeeper Thibaut Courtois. Three minutes later, Malen crossed for Jamie Bynoe-Gittens to score Dortmund's second, sprinting past a dozing Lucas Vázquez at the far post.

It didn't take long for Madrid to spark into life, Rodrygo -- back in the XI here in his favourite competition after three consecutive games on the bench -- and Jude Bellingham both hitting the woodwork within seconds of each other. But then it was Dortmund who again came closest to adding a third before the break, Courtois saving at full stretch from Julian Brandt.

The Bernabeu crowd whistled their team off the pitch at halftime, their pride stung. In the second half, a reaction felt almost inevitable. It arrived in the 60th minute when Antonio Rüdiger's powerful header from Kylian Mbappé's cross made it 2-1, before Vinícius made it 2-2 minutes later, after a nervous wait for an on-field offside call to be overturned.

Then, Madrid had to wait. They pushed for a winner, as Dortmund tried to hang on, and occasionally threaten, if they could, on the break. When it came, Madrid's third goal arrived from Vazquez, before a breathtaking late double from Vinícius left the result in no doubt. By the final whistle, Madrid's poor first half felt like a distant memory, the win ultimately so comfortable, so overwhelming, that what came before it could almost be dismissed as an irrelevance.

Vinícius carried the match ball off the pitch and will take the headlines as the game's outstanding player. As preparation for Saturday's El Clásico against Barcelona in LaLiga, it doesn't get much better, even if Madrid's first-half shortcomings suggest there are still plenty of reasons for concern.

The nature of this new Champions League format, with only 12 of the 36 teams being eliminated after the league phase, means that even with a defeat, Madrid might well have qualified for the knockout phase anyway. And it's worth remembering that they weren't immune to the occasional group stage slip-up -- remember Moldova's Sheriff Tiraspol winning 2-1 at the Bernabeu in 2021? Madrid went on to lift the Champions League that season.

But in the end, there was no slip-up here. There was business as usual. After this second half, Madrid will be talked about as being among the favourites to win the competition again in 2025. And with Vinicius in this kind of unplayable form, it's hard to argue.