Slovakia pulled off one of the biggest upsets in European Championship history with their victory over Belgium – but it could have been prevented.

Ranked third in the world, Belgium were favourites to top Group E before kick-off but now find themselves playing catch-up after a wasteful performance in Frankfurt and a “scandalous” refereeing decision.

Chances came and went and Romelu Lukaku squandered several before having two second-half goals ruled out by the video assistant referee (VAR).

The first of which he was clearly offside, but the second was a more controversial decision with less than three minutes of normal time remaining.

Referee Halil Umut Meler was sent to the pitchside monitor before disallowing the goal for handball in the build-up by Lois Openda.

The Belgium substitute was in full motion as he fell into the ball while tussling with Slovakia defender Denis Vavro, with his arms seemingly in a natural position.

“That is scandalous. It is ridiculous, it really is,” former Chelsea striker Chris Sutton said on BBC Radio 5 Live as Belgium’s celebrations were quickly squashed.

“Openda doesn’t intentionally push the ball into his path. That is harsh. In the Premier League, that goal would stand.”

Nonetheless, Belgium came away with nothing after Ivan Schranz capitalised on a loose pass by Manchester City’s Jeremy Doku in the first half to give Slovakia a hard-earned 1-0 win.

Doku’s mistake and Lukaku’s wastefulness proved costly as Belgium lost for the first time in 15 matches under manager Domenico Tedesco.

They have failed to score from each of their past 47 shots in major tournaments, and missed four big chances in a Euros game for the first time since 1980.

“I don’t think anyone saw this result coming with the talent and quality that Belgium have in their squad,” added Sutton.

“They had chances. This is going to be one of Slovakia’s most famous victories.”

It certainly is as Slovakia, ranked 48th in the world, revelled in a first win against one of the world’s top three.

When the full-time whistle went in Frankfurt, Slovakia’s substitutes and staff sprinted on to the pitch to celebrate, standing arm-in-arm in front of their supporters, bouncing and chanting.

“We gave it our heart. We didn’t win it by being better, but by being happier,” Slovakia defender David Hancko said.

But for Belgium boss Tedesco, it was an unfamiliar feeling of defeat as he faced questions about how his side did not convert one of the 16 chances they had.

“We knew before that one day we would have to lose a game and unfortunately it’s today. Of course we created many big chances,” he said.

“We knew they would come and press. We handled it well, we won good balls and the only thing that was not perfect was the missed chances. We had many and big ones.”

With 45 places separating Belgium and Slovakia in the Fifa rankings, this was statistically one of the biggest upsets in European Championship history.

The late VAR decision to rule out Lukaku’s equaliser because of handball by substitute Openda played a role.

Belgium boss Tedesco said he wanted to be a “fair loser” and did not want to give more of his opinion on the decision.

Christina Unkel, ITV Sport referee analyst, said: “The deliberation interpretation has recently changed.

“However, this is considered a deliberate offence as the arm is near the shoulder level because the arm is extended and the touch helps control the ball.”

But while Sutton believes the VAR decision was incorrect, he stressed that Lukaku had enough earlier chances to score.

“In truth, it was lousy from Lukaku in the first half. It was three huge opportunities that he normally gobbles up,” added Sutton.

“He could have had the Golden Boot [awarded to the tournament’s top goalscorer] wrapped up already. Slovakia haven’t actually created too many chances – but it is about Belgium being wasteful.”

Tedesco was not concerned, despite Belgium’s profligacy also playing a role in their premature group-stage exit at the 2022 World Cup.

“Lukaku’s been playing for Belgium for a long time and knows very well how to score goals. He showed that time and time again. Tonight he did score – but it was disallowed,” he said.

Doku’s mistake also proved costly as Belgium proved to be their own worst enemy on a forgettable night in Frankfurt.

“Of course it hurts. It hurts for him, for me and the team – but it’s part of the game. You will not score any goals without errors. It can happen,” added Tedesco.

“Slovakia had many errors tonight and that is why we have to score. We speak more about this error because it was the deciding goal.”

They have work to do now as they travel to Cologne to face group leaders Romania on Saturday, hoping to avoid another early exit from a major tournament.