Egypt were 2-0 up with 11 minutes left of their last 16 clash against the holders Argentina, agonisingly close to one of the great World Cup upsets, only to concede three goals in the closing stages and go out.
They were picked apart at the end of the game by a Lionel Messi-inspired comeback, but Hassan insisted his team were better.
"I'm going home and won't be watching any more games from the tournament," he told a press conference.
"What happened to us wasn't fair. We should have had a penalty, a goal was disallowed, and I don't know why it was disallowed."
Egypt netted in the 62nd minute through Mostafa Zico, but a VAR check found there was a foul from the Egyptians in the buildup.
They also claimed a late penalty after a tug on Hamdy Fathy, and their anger was exacerbated by Argentina going down the other end and scoring a 92nd-minute winner.
"Even if the goals came from mistakes, the biggest mistake is not getting what you're entitled to from those responsible for making the decisions," said Hassan, whose press conference was a long litany of complaints.
"I'm the type of person who hates losing. And when it's a defeat that feels unjust like today's, I can only tell the fans not to be upset. We wanted so much to give them more joy," he added.
"But what made me happy was that my players followed the game plan on many occasions and worked very well."
Egypt had been surprisingly attacking early on in the game, a departure from Hassan's usual tactic of playing with a tight defence and looking for counter-attack opportunities.
It helped them take an early lead, but it was the heroics of goalkeeper Mostafa Shoubir that ensured they remained in front by halftime.
"I'm very, very satisfied with the effort they put in. Most of our players come from the Egyptian domestic league, while many players in other national teams are based in Europe and live in that professional environment," Hassan added.
"Yet with predominantly local players - besides Mohamed Salah and Omar Marmoush - we were able to compete with anyone."
FIFA World Cup 2026
The 2026 World Cup took place from June 11th to July 19th in the United States, Canada and Mexico. The tournament featured 48 national teams and was won by Spain, who beat Argentina in the final.
Full schedule and results | Group standings and bracket | Past winners of the tournament | Our team of the tournament | About the 2030 World Cup