Sherrock's victory over Littler meant the event immediately ended, leaving the five remaining amateurs unable to get their shot at the £501,000 prize. With Littler on stage for more than two hours, he inevitably tired as his standard dropped, allowing Sherrock to take advantage and win in a 15-dart leg in match number 15.
Littler had raised his game earlier, hitting a maximum 180 followed by a 158 checkout, the highest of the night, to defeat a fellow teenager in only 12 darts. He was the only other player, apart from Sherrock, to cause Littler a fright.
The packed crowd in Manchester was in boisterous mood with many fans in fancy dress, during a surreal night of action where some of Littler's opponents had never played a competitive game of darts.
Hearn reappeared to present Sherrock with a huge cheque for her life-changing victory.
She had been closest to the bull to start first and hit a 180, only the third maximum of the night, before taking out double 20 to clinch the prize.
"I'm really proud of myself, I rise to the occasion,"Sherrock said.