Dave Wattam scored a hat-trick of tries as Haywards Heath geared up for the games which could ensure a Trophy and promotion double.
Heath were 35-8 winners at holders Worthing in their delayed Sussex Trophy semi-final on Sunday.
The win sets up a final against Chichester on Easter Saturday.
Heath are also on course for a promotion play-off which could send them into the national leagues.
They overturned an early five-point deficit to see off Worthing, who were just pleased to avoid any major injuries ahead of their title decider with Beckenham.
Victory was built on a superb display from the front five, who Heath felt ground down their hosts and set the scene for five second-half tries.
Lock Rick Ure was especially impressive on his return from injury, Emmet Edwards produced one tremendous tackle in his busy display and Chris Sherwood, Gordon Denslow and Nick Dinsdale also earned high marks.
Winger Henry Goodburn, a veteran of six Trophy triumphs in recent seasons, said; "We wanted to beat Worthing on their own pitch having lost there in the semi-final last year and I think we outplayed them.
"They probably had their minds on the forthcoming league game but we have got a big league game coming up too. We really wanted to get out cup back as well.
"We conceded an early try but we defended well, especially in our own 22, and Dave Wattam was a nuisance to Worthing throughout the second half."
Heath were given fresh impetus with the second-half introduction of Andy Cook, Nick Killick and Alex Meredith while Worthing took some of their senior players off.
Cook, Giles Goodburn and Glenn Rankin all scored tries with Owen Ashton adding a conversion and a penalty.
Heath now look towards next Saturday's league game at Thanet Wanderers as they plan for a promotion play-off.
Victory could even take them up as champions in the unlikely event of leaders Southend failing at lowly Norwich.
Worthing know a point at home to Maidstone will definitely see them finish top of London Two South, which would be their second successive title.
Dave Davis scored their early try on Sunday and Ben Coulson's penalty brought the score back to 8-8.
Coach Ian Davies said: "We achieved what we wanted which was to avoid serious injury.
"I'm not disappointed. If we lose next Saturday, then I'll be disappointed."
Hastings and Bexhill beat Hove Exiles 47-3 in a club match with Paul Sandeman scoring two tries and adding six conversions.
Jimmy Adams, Nick Edmonds, Neil Redman, Ben Walcott and Steve McManus also got over.
Hooker Ben Davies and winger Shane Potter, both 19, enjoyed good debuts while the young H&B side were given valuable experience playing against a veteran Hove outfit with impressive rucking and mauling know how.
Christian Wilks and Huw James scored two tries apiece as Lewes II beat Royal Sun Alliance 63-3.
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