Aidan O'Connor came close to getting United over the line with 30 from 23 balls before being caught out by bowler Trillo (2-24) when 10 were needed from two deliveries.
Daniel Worsfold (4-23) and Adam Heap (2-30) were the other main scalp takers.
So that put the Renegades into the afternoon final with the Wicket Warriors, who had defeated the Hunterville Hackers by 17 runs in the other semifinal.
Inspirational Warriors skipper Sreejith Sreekumar scored 50 from 29 balls as his side was dismissed for 156 at the end of their 20 overs, with Hunterville's Will Lamp (4-27) and James Wilson (3-9) the pick of the bowlers.
Hunterville couldn't keep up with the run rate and batted out to 139-9, losing wickets outside of the main contributors in skipper Shane Ratima (39), Andy Locke (30) and Wilson (33).
Sabari RJ took an important 4-39 to get three of their potential partners as well as Wilson himself after a 10-ball slog.
Yet in the final, the Wicket Warriors could not put up another challenging total, as the Renegades held them to 107 all out in the 19th over.
Openers Mehul Barot (20) and Vinu Chacko (15) started well enough, but the wickets tumbled after that, aside from Sabari RJ surviving for 25 from 41 balls.
Roger Moore (4-15), Trillo (2-14) and Worsfold (2-27) put the pressure on.
Renegades then backed up their bowling with a controlled run chase – reaching 110-2 with five overs to spare.
Again, all the batsmen made a contribution, as opener Moore (38 not out) carried his bat through, sharing in partnerships with Trillo (18), Heap (25) and Garry Sandhu (18 not out).
Sabari RJ and Chacko took one wicket each.
The Renegades focus now turns to trying to win their fourth Bullocks Pro 40 title, as they currently lead the five-team competition with four rounds remaining until finals day on March 14.
United are currently in second place, followed by defending champions the Matt Burke Engineering Marton Saracens, then Wicket Warriors and Whanganui Collegiate 2nd XI respectively.