• Many thousands more watched the game back home in pubs, fan zones and schools, where lessons were suspended.
• Children in Wales were able to watch the match after the Welsh government told schools they could cancel lessons to show it.
Wales fans have been left dejected after World Cup optimism turned into heartbreak.
The country's first World Cup for 64 years looks set to end at the first hurdle after a last-gasp - but deserved - 2-0 defeat against Iran in Qatar.
Up to 6,000 Welsh fans packed the Ahmad bin Ali stadium in Doha, double the pre-tournament estimates.
Many thousands more watched the game back home in pubs, fan zones and schools, where lessons were suspended.
Children in Wales were able to watch the match after the Welsh government told schools they could cancel lessons to show it.
Thousands had made the long journey to Qatar to watch the second game of Wales' return to the World Cup after a 64-year absence.
There had been a quiet confidence among many before kick-off following the second-half display against USA.
However this match, which kicked-off in 31C (88F), looked a game too far in the heat, according to fan David Crean, who had travelled from Cardiff with his son Jack.
"I'm gutted. We just ran out of puff. We didn't turn up and just couldn't keep up with the pace," he said.
"I just hope England win tonight [against USA]. If not, I don't really want us to be humiliated by them."
While The Red Wall of Wales fans dominated one end of the ground, Iranian fans took over most of the rest, and were loud throughout the game.
Mr Crean added: "It was something completely different. My ear drums have gone."
Matt James, 33, from Caldicot, Monmouthshire, added: "It was an incredibly hostile atmosphere, like an away game. We would have taken a 0-0 but to lose in injury time like that is gutting."
"It's a tough pill to swallow, but we will be ok tomorrow," said Becky Green, 48, from Llantwit Fardre, Rhondda Cynon Taf.
"After the way we played in the second half against the USA, I thought we were in with a chance. But it wasn't meant to be."
Dad Eric, 69, was also pragmatic and said: "We have seen worse things over the years as Wales fans.
"It's just great to be at a World Cup."