Slovakia have pulled off one of the biggest shocks in European Championship history, defeating world No.3 Belgium 1-0.
With Slovakia ranked 48th in the world it is the event's biggest statistical upset since the FIFA rankings began in the early 1990s.
Belgium will feel they were unlucky. Romelu Lukaku had one goal chalked off for a tight offside and another for a debatable handball in the build-up, but Slovakia defended well after Ivan Schranz pounced on a seventh-minute error by Jeremy Doku.
The surprise in Frankfurt followed another unexpected result in Munich where Romania ended a near-quarter-century drought with their first win at a major tournament since beating England at Euro 2000, defeating Ukraine 3-0.
In the late game favourites France edged a tight, fractious opener against Austria in Dusseldorf. It was decided by an own goal from Max Wober, who inadvertently headed a Kylian Mbappe cross into his own net 38 minutes in.
The contest was mostly notable for a bad miss by Les Bleaus skipper Mbappe, who later left the match with a yellow card and what may be a broken nose, and an outstanding display by N'Golo Kante.
Slovakia's most notable win since defeating Italy at the 2010 World Cup was preserved by defender David Hancko's brave goal-line block that left him sprawled with a head injury inflicted by a teammate's knee.
That came in the 62nd minute, from substitute Johan Bakayoko's close-range shot, just seven minutes after Lukaku's first goal was overturned by the automatic offside system.
A Video Assistant Referee (VAR) intervention in the 86th disallowed Lukaku's powerful shot because of a handball by Lois Openda in the build up.
Lukaku set a competition record of 14 goals in qualifying, yet failed to score in a wasteful first half including twice before Slovakia led.
In Bavaria, after veteran Nicolae Stanciu punished a distribution error by Real Madrid keeper Andriy Lunin with a superb 29th-minute strike, Romania swept their opponents away.
Eight minutes into the second period Razvan Marin added a second, also from distance, with Lunin again at fault. Shortly before the hour Denis Dragus turned in a cross from Dennis Man from a neat short-corner routine.
"It's a memorable victory, a historic victory for the Romanian people," coach Edward Iordanescu said.
It was Romania's first tournament match since Euro 2016, when his father Anghel was coach.
The match was a desperate disappointment for a Ukraine side seeking to give their beleaguered homeland some cheer.
In Munich prior to the match parts of a stand from Kharkiv's Sonyachny stadium, that was built for Euro 2012 and destroyed in 2022 by Russian troops, was on display to highlight the damage done to the country's sporting infrastructure by the invasion.
Elsewhere, a German YouTuber who managed to penetrate security to gatecrash the opening match between Germany and Scotland with fake accreditation and a mascot costume has been given a stadium ban for the rest of the tournament.
More seriously, the man shot in the leg by police prior to the Netherlands-Poland match in Hamburg has been charged with attempted manslaughter.
The man had been holding a Molotov cocktail - a home-made incendiary device, and what police described as a pickaxe or axe-like object.
With agencies.
