The 17-year-old hit a sublime nine-dart finish during the contest, triggering a huge response from the crowd in attendance and earning him a hug and ovation from his opponent.
The nine-darter came in the 11th leg at the tail end of a pulsating tie between the two stars with both trading blows, exchanging leads and breaking one another's throws.
"I'm just glad to get over the line," Littler told the PDC. "I lost the two legs after I hit the nine so I'm relieved to get the win.
"It's always good to be involved in a good game; me and Rob have battles and we bring the best out of each other.
"I'm really happy to hit a nine-darter, I prefer 144 to 141 to finish a nine because when the first treble 20 goes in I'm confident of following it with another.
"I know the spotlight is on me because I've done so well but I just play my darts and get on with it. I just do what I do."
Littler averaged 103.76 to Cross' 108 and both were level on 50 per cent for finishes - although Littler landed considerably more 140-plus checkouts.
"I wanted a big display and I got a big display," said Cross after his fighting defeat.
"I missed a few chances but I can't be bitter about them.
"Luke is special, he has such a bright future in front of him; the nine was amazing."
'The Nuke' beat Jermaine Wattimena 6-2 and Ricardo Pietreczko 7-3 on his way to the final - with the latter strangely accusing Littler of being "arrogant" on his Instagram after confronting the British darts star at the end of their match before storming off the stage.
Writing via an Instagram story, Pietreczko wrote: "I really appreciate the fact that he can play a game like that at such an age. But I hope his arrogance punishes him."
Ahead of returning to the Oche against Cross, Littler took to social media with his take on the exchange, saying: "No idea what I did wrong, no idea what he said. He said something then 'don't do it again.'"
Cross had defeated Ryan Searle 6-2 and Gerwyn Price 7-3 earlier in the evening but was unable to put away Littler - who knocked the world number five out of the World Championships at the semi-final stage earlier this year.
Littler takes home £30,000 in prize money for winning the 2024 Blåkläder Belgian Darts Open event.
