For the first time in some time, it felt as if Arsenal was the team with the impetus, the team going places, like Tottenham was adrift. It felt as if Arsenal could be confident, that it could lay down a marker. The Emirates was noisy and hopeful and bathed in sunshine.

And then David Luiz took one step forward. He bought Son Heung-min’s feint, and behind him the space unfurled. Spurs burst through. Bernd Leno, the Arsenal goalkeeper, parried Erik Lamela’s shot straight at Christian Eriksen’s feet, and suddenly Arsenal was two steps back. More, in fact. Arsenal was back at the start.

Arsenal’s Emery is new, in his post for only a year. Many of its players are new, too, or new in soccer terms: Of the 11 who started this north London derby, Granit Xhaka was the longest-serving as a senior player, and he arrived in 2016.

And yet it is one of sport’s curiosities that — just as a car can somehow be the same, still yours, even when the engine has been replaced, and the windshield is new, and quite a lot of the bodywork is different — teams can have traits that jump from generation to generation, characteristics that endure even as the parts that produce them change.

It does not matter who plays for Arsenal, it seems. No matter the name on the jersey, there is a tendency for self-destruction and, at times, for sheer, bloody-minded stupidity encoded deep in the DNA of the club.

It has become one of the team’s calling cards, its ability to hurl itself headlong into trouble. It does not shock the Emirates anymore, not really. There is no intake of breath when Xhaka, the captain, bafflingly launches himself at Son from several yards away inside the penalty area. There is no surprise when he misses, and misses comfortably, and gives away a penalty kick. There is anger when Harry Kane converts it, to give Tottenham a two-goal lead, but it is a resigned, familiar anger. Arsenal’s fans are used to this. Sadly, troublingly used to it.