Sporting new threads, world number one Humphries turned on the style at his 'home' event; clawing back from an early deficit and surviving a furious late rally from Littler to take the win.
With that nail-biting victory, Humphries (31) narrows the gap to Littler (38) atop the Premier League table - he’s now just seven points behind the teenager, who’s been tearing up the league all season.
Gerwyn Price (24) is also a victor tonight as he's punched his ticket to finals night, ahead of Michael van Gerwen (20) and Nathan Aspinall (19).
Van Gerwen and Aspinall are set to face-off in the quarters next week, which means one of them won't be able to catch Price. It'll essentially be a knockout game in disguise.
Catch up on the night's action below:
Quarter-finals
Welsh star Gerwyn Price got the evening underway by defeating Rob Cross by the slender margin of 6-5.
En route to the final, Littler started his night by beating Nathan Aspinall 6-4 in a thrilling encounter.
Humphries was able to overcome the mighty Michael van Gerwen 6-4 in an equally exciting clash.
To round out the semi-finals, Stephen Bunting beat Chris Dobey 6-5 as 'The Bullet' found the double when it counted.
Semi-finals
Littler made relatively short work of Price, who won night 12 in Liverpool a fortnight ago, by beating him 6-3.
Humphries ensured he would meet his namesake in the finale by beating Bunting 6-4 in a competitive affair.
Final
The final offered up some fast and furious darts as two of the world's best players fought for victory.
Littler came out firing, racing to a 2-0 lead and looking every bit the teenage titan.
But Humphries, ever the composed customer, then claimed five of the next six legs to lead the match 5-3.
Just when it looked as if the world number one would simply claim the win, 'The Nuke' fought all the way back to 5-5.
But when the final leg came, it was 'Cool Hand' Luke who held his bottle to deservedly edge it in Leeds.