Andrew Balbirnie's 88 helped Leinster Lightning defeat the North West Warriors by 54 runs in Saturday's Inter-Pro one-day game at Strabane.
With the weather intervening, Leinster only managed 28 overs but Balbirnie's 98-ball knock enabled them to reach 158-5 with Stuart Poynter hitting 30.
That left the Warriors with a victory target of 215 from their 50 overs under the Duckworth/Lewis format.
However, the Warriors were all out for 160 in 23.1 overs.
Balbirnie is a member of the Middlesex squad and has just signed a two-year contract extension with the English county side.
After losing Jason Milligan for a duck, the North West looked on course for victory as David Rankin's partnership with Stuart Thompson helped them reach 55-1.
But after Thompson departed for 30, wickets began to tumble at a regular rate even though Rankin hit 44 with Gary McClintock scoring 46.
Balbirnie took two wickets with John Mooney only taking a dismissal although the pick of the bowlers was Albert van der Merwe who produced figures of 3-30 from his six overs.
Leinster's margin of victory ensured what could well be a crucial bonus point, which takes them two points clear at the top of the table.
The trophy will be decided next month when Leinster face the Northern Knights at Waringstown on 14 September, followed by a clash at Rathmines six days later.