A woman from Cairns, Australia, used Siri to call an ambulance for her one-year-old daughter when she stopped breathing.
Stacey Gleeson grabbed her iPhone and ran to the child's room to help her but dropped it as she turned on the light.
She shouted at the handset to activate Siri and told it to get the emergency services on speakerphone as she began CPR.
Ms Gleeson told the BBC she feels it may have saved her daughter's life.
She instructed Siri to call an ambulance on speakerphone and was able to communicate with the emergency services while resuscitating Giana.
Giana, who had been battling a chest infection and bronchiolitis, was breathing again when the ambulance arrived,
The child made a full recovery and doctors have told Ms Gleeson there was no lasting damage, but that every second had been vital.
It happened in March but the story has now gone viral after Ms Gleeson contacted Apple, who alerted Australian news outlet 7 News.
"As cheesy as it sounds I wanted to say thank you," she told the BBC.
"I've only had the phone since the start of the year.
"I had played around with Siri, I thought it was a fun feature. Now I have that feature turned on all the time and it will never be turned off again."
She had previously used it to call her husband Nic, who is in the Navy, on loudspeaker while getting the children ready for bed.
The function doesn't work on all iPhone models but Ms Gleeson has an iPhone 6S.
She said that even if she hadn't dropped the phone, she may have struggled to dial the number in the heat of the moment.
"Saving me the trouble of having to physically dial emergency services was a godsend."