Having been sent in, ND rattled up 170 for six, the critical point being the rousing 90-run stand in 57 balls between veteran lefthander Flynn and the bustling Watling.
Each hit 53, off 30 and 37 balls respectively, to ensure Lahore would face a challenging task in conditions perfectly suited to Southee and Boult's talents.
From 19 for five in 5.4 overs there was no hope of a comeback. Southee bowled Nasir Jamshed with a lovely, full inswinger in his first over.
Boult had the ball on a string, swinging it this way and that to leave batsmen bemused and befuddled as they headed back to the pavilion.
One big inswinger bowled key batsman Umar Akmal and, had Saad Nasim not clouted 58, their only player to make double figures, Lahore would have got nowhere near their eventual 98 off 18 overs.
Southee took three for 22, Boult two for 12 from their four overs apiece.
Class players are calling the shots, but they are expected to face their toughest challenge against Mumbai.
Lasith Malinga and Harbhajan Singh head the bowling cast; Mike Hussey, West Indian Lendl Simmons and big-hitting Kieron Pollard are influential figures with the bat.
ND lead the four-team qualifying competition - from which the top two progress - with a 2.684 differential.
Mumbai are second and four points back with Lahore on -1.496.
