After two weeks of washouts, Westbury and South Launceston made the most of Thursday night T20 cricket.
The sole team to have two victories in the two full games, reigning premiers Westbury accounted for Launceston by 29 runs in a rematch of last year's T20 grand final.
Batting first, the Shamrocks made 9-113 before bowling the Lions out for 84.
Losing Jesse Digney early, the Shamrocks' top order of Matthew Battle (41), Dan Murfet and Oliver Wood (21) bounced back with key partnerships of 44 and 31 before losing 8-25.
Jono Chapman provided some lower-order stability with 20 off 18 as first-grade debutants Jonah Cooper (3-16) and Roy Penn (2-9) got in the wickets alongside Dravid Rao (2-35).
In chase, Dean Thiesfield's run-a-ball 29 and Rao's quick-fire 18 off 12 were the only batting highlights as the Shamrocks shared the wickets around.
Joel Lloyd and Kieran Hume (both 2-15) were the multiple wicket-takers as other bowlers Chapman, Wood, Liam Ryan and John Kedey snagged one each.
A strong South Launceston batting performance made light work of Mowbray's total as South won by eight wickets.
Setting the Knights 8-113, Mowbray were unable to get through Sisitha Jayasinghe until it seemed too late, as the hard-hitting opener hit 60 off 45 balls.
Putting together a 83-run stand with Jeremy Jackson (39* off 41), the pair took the game away from the Eagles with relative ease.
Earlier, a 41-run stand between John (15) and Spencer (28) Hayes set a solid platform for Mowbray but only Lachlan Dakin (13) and James Storay (15) made double figures from there as they batted out their 20 overs.
Youngster Riley Donlon (3-15) and Ian Labrooy (3-31) led the bowlers against Donlon's former junior side, before sitting back and watching their batters go to work.
Jono Jones (1-26) and Ben Spinks (1-30) took wickets for Mowbray.