A determined fight-back would see Westmoreland haul himself up to fifth position, though his hopes of making in-roads into the erstwhile five point margin between himself and Kirkham was hampered by the latter finishing in sixth himself, albeit a long way behind.
It means the two head into the race two decider split by just four points, though Westmoreland at least has a chance to make amends after his impressive charge earned him the fastest lap and with it another pole position. Kirkham will start on row three in seventh place.
Elsewhere, Tommy Bridewell's hopes of a late charge into the Title Showdown were scuppered by an engine problem that forced him out whilst running in fifth position, while seventh wasn't enough to keep Chris Walker in contention either.
His equal-best result of the season, Jakub Smrz held off PJ Jacobsen to finish in eighth position, while Barry Burrell picked up a strong top ten finish on the Quattro Plant Kawasaki.
Peter Hickman recovered from his qualifying crash to finish in 11th, while Josh Waters maintained 12th despite an off-track moment. Making late gains after struggling early on, Kiyonari finished 13th, ahead of Michael Rutter and Dan Linfoot.