Lamine Yamal has become the youngest player to appear in the men's European Championship, as Spain's new generation brushed aside Croatia's challenge 3-0 in their opening match.
Meanwhile, defending champions Italy recovered from the shock of conceding the fastest goal ever scored at a European Championship to beat Albania 2-1.
Yamal, aged 16 years and 338 days, also became the youngest to set up a goal at the tournament when he crossed for Dani Carvajal to score Spain's third goal before the break in the Group B match at Berlin's Olympiastadion.
Nico Williams, 21, starred on the other flank for Spain, which is attempting to win its fourth European title.
Midfielder Fabián Ruiz scored one goal and set up the opener for captain Álvaro Morata in a dominant performance from Spain.
"We have to stay wary, stay calm and be proud. We have to keep improving in the next game," Spain coach Luis De La Fuente said.
"We just have to stay calm and be professional."
Spain goalkeeper Unai Simón saved a penalty in the 80th minute from substitute Bruno Petković, who thought he scored when Ivan Perišić sent in the rebound.
But the goal was ruled out after a VAR review as Perišić had encroached on the penalty area before Petković took the spot kick.
The Croatia fans, who greatly outnumbered their Spanish counterparts, tried rousing the team before the end in Berlin, where the final will be played on July 15, Australian time.
Croatia star Luka Modrić, who played at Euro 2008 before Yamal was even born, was unable to assert his usual influence.
Modrić, 38, was given a warm embrace by Real Madrid teammates Nacho and Carvajal before the teams walked out onto the field, getting a kiss on the cheek from each.
When Modrić and Mateo Kovačić went off in the 65th minute, it was clear Croatia coach Zlatko Dalić was already thinking of the next match.
"They played for an hour and we realised we have two difficult matches in front of us. We didn't want to force them to the end," Dalić said.
Against Italy, Tens of thousands of raucous, red-shirted Albania fans had the Dortmund BVB Stadion rocking when Nedim Bajrami blasted home from an angle after 23 seconds.
Bajrami capitalised on a rash throw-in by Italy defender Federico Dimarco.
The goal smashed the previous record held by Russia's Dmitri Kirichenko, who scored after 67 seconds against Greece in 2004.
Amid the din, however, Italy held its nerve and equalised in the 11th minute when Alessandro Bastoni headed home when a short corner was swung in to the far post by Lorenzo Pellegrini.
Nicolo Barella — returning to the national side after injury — put the Azzurri in front five minutes later when he slammed home from outside the box.
Croatia next plays Albania in Hamburg on Wednesday night, Australian time, while Spain faces Italy in Gelsenkirchen on Friday morning, Australian time.
AP/Reuters