The visitors made a dream start when Angelo Davids intercepted a pass inside the opening five minutes and sprinted clear to score beneath the posts, with Sam Francis adding the conversion to hand the Lions a 7-0 lead.
But Newcastle hit back through Alex Hearle, who finished well after Boeta Chamberlain exposed a fractured Lions defensive line, and Ethan Grayson's conversion levelled the scores. The Lions regained control soon after, earning a penalty which Francis calmly slotted to restore a 10-7 advantage.
Despite enjoying long spells of possession and territory for the remainder of the first half, the Lions went into half-time holding a slim three-point lead and knowing they had left points on the field.
The second half followed a similar pattern, with the Lions dominating the collisions and defending strongly while struggling for accuracy in key moments.
Newcastle grew in belief as the clock ticked down and eventually found a decisive breakthrough in the 79th minute when Murray McCallum forced his way over after sustained pressure. Grayson's conversion sealed the contest as the Lions came away empty-handed.