Spinners Warner (5-25) and Ian Booth (2-27) put the brakes on after the hosts had made a promising start in reply to Swanage’s 202 for nine.
With Tom Caines and Simon Woodruff both looking in good form, Wimborne & Colehill had reached 100 for two from 23 overs as Swanage struggled to make inroads.
However, Mike Salmon’s sharp catch at slip split the partnership as Warner made the breakthrough to see off Woodruff (18) in his second over.
James Williams was caught behind by Lewis Kirby off Booth’s off-spin and the contest was still delicately poised at the drinks break with the hosts on 105 for four.
Warner and Booth then started the squeeze, the pair working in tandem to ensure the pendulum would swing in Swans’ favour.
A moment of brilliance from Warner ended the Velcro-like grip Caines (47) had on his stay at the crease, a beautiful googly baffling the batsman and trapping him in front.
Warner ripped apart the Wimborne & Colehill lower order and only Jim Miller’s unbeaten 36 saved the hosts from further blushes as they were dismissed for 169.
Earlier, Swanage’s total had been built around a third-wicket stand of 85 between Matt Thomas (59) and Wimborne old boy Francis Kerrins (55) with James Williams (3-42) and Joe Weld (3-34) among the wickets.
- Stand-in skipper Steve Trembath led from the front as Broadstone registered a four-wicket victory over Parley at the Delph.
A devastating opening spell from Trembath saw him reduce Parley to 42 for six, the paceman ripping through their top order to claim all six victims.
Ollie Green (56) led the Parley recovery and, with Jack Rowett (32), Luke Condron (22) and George Wilson (21) all chipping in, the visitors repaired the early damage to post a challenging 199.
James Rimmer (36) helped settle the nerves in the Broadstone camp following the loss of opener Luke Carter in the second over.
And after Sean Hatton (24) had gone with the score on 127 for five and Daniel Cook at 134 for six, Trembath (63) dominated an unbroken sixth-wicket stand of 66 with Carlyle Collins to see them home, his destructive 38-ball knock seeing him crack six fours and four sixes.
- Jamie Thomas paved the way for leaders Poole Town to make light work of easing to a seven-wicket victory over bottom-placed Ferndown Wayfarers.
Thomas (4-22) claimed the top order before Dameth Gunawardena (3-21), Ciaran Quinn (2-2) and Joe Wilson (1-22) combined to polish them off for just 94 (Karl Jensen 23, Jordan Warren 21*).
Brewster Surridge (38) ensured the Poole reply would get off to a positive start before Badral Alam (34) remained undefeated as they cruised to 95 for three.
- Weymouth (121-4) beat Stalbridge 184 by six wickets after being set a revised target of 120.