The Afghans made their World Cup bow in Canberra against the Test-status South Asians, completing another step in their fairytale rags-to-riches story.
The war-torn country has taken to cricket with a passion and millions are expected to follow the match via TV, radio and social media.
With the match barely a quarter of the way through, the US embassy's official Twitter account posted a message hailing Afghanistan's "victory".
"Congratulations to #Afghanistan for their win over #Bangladesh in the Cricket World Cup #CWC15 #AFGvsBAN," the message said.
"Premature posting but we are still cheering for team Afghanistan at the #CWC15! #AFGvsBAN," the embassy tweeted.