On his Premier Division debut, Henderson, who is captain of Sussex u14s, hit 82 not out from 89 balls batting at nine to see Roffey home.
Roffey were chasing 224 to win after Ben Fitchet had hit 95 for Mayfield. The reigning champions were struggling at 100-7 but a partnership of 87 between Henderson and Mike Norris (58) gave them a chance. After Norris and Alex Collins went, Luke Barnard joined Henderson needing 20 still to win and they got over the line in the 52nd over. Steven Harman took 4-52 for Mayfield.
Second-placed Brighton (277-9) also won by one wicket, beating Eastbourne (276-9).
James Hockley top-scored with 63 for Eastbourne while Matt Machan took 4-91. In the reply, Steven Crosby was the star hitting 113 with Machan supporting with 55. Fergus Guppy and Jonathan Goldstraw got them over the line. Ben Twine took 4-44 for Eastbourne.
William Taylor took 5-30 and Tom Haynes hit 91 as East Grinstead (226-4) beat Middleton (224 all out) by six wickets. Mahesh Rawat fell one short of his century for Middleton.
Preston Nomads (224-6) enjoyed a four wicket win against Horsham (221-9). Tom Clark hit 91 for Horsham while youngster Dominic Shepheard hit 47 not out in the reply.
Three Bridges (280-7) enjoyed a comprehensive 135 run win against Cuckfield (145 all out). David Winn (62) and Adam Jones (79 not out) were the stars with the bat for Bridges.
In reply Mike Rose took 4-26.
In Division 2, Ricardo De Nobrega hit a brilliant 153 as Hastings (314-5) beat Billingshurst (269 all out) in the top-of-the-table clash.
Elliot Hooper (55) and Ryan Hoadley (57) also batted well as Hastings posted a big score. Max Hollander hit 83 for Billingshurst but Adam Barton (5-78) lead the way with the ball.
Joe Ashmore (4-25) and Roy Kaia (3-19) starred as Bognor (72-1) hammered Burgess Hill (68 all out).
Goring (271-3) enjoyed a 122-run win against relegation rivals Ifield (149 all out). Danny Pittham (81 not out) and Stuart Carter (100 not out) put on an unbeaten stand of 169 for Goring.
Kellon Carmichael (4-50) and Oliver Watkins (4-42) bowled Goring to the win.
Ben Van Rensburg (4-17) and Jethro Menzies (92 and 4-33) were the stars for Haywards Heath (199 all out) stunned St James’s Montefiore (80 all out).
Jonny Phelps hit 52 to support Menzies in the Heath innings.
Abishek Raut took 6-27 as Chichester (100-6) beat Lindfield (96 all out).
Division 3 West: Broadwater 207-6 lost to Worthing 225 all out; Littlehampton, Clapham & Patching123-2 beat West Chiltington & Thakeham 122 all out; Roffey 168-2 beat Ansty 165 all out; Stirlands 191-8 lost to Pagham 192-2.
Division 3 East: Crawley Eagles 202-7 beat Rottingdean 36 all out; Eastbourne 2nd XI 206 all out beat Seaford 192 all out; Hastings & St Leonards Priory 2nd XI 227-4 lost to Bexhill 1st XI 228-2; Portslade 184-9 lost to Brighton & Hove 2nd XI 185-4; Preston Nomads 2nd XI 277-7 beat Rye 1st XI 207-8. Highlights: Rilwan Mohamed 6-11 for Crawley Eagles; Fraser McHale 104 for Eastbourne 2nd XI; Cameron Burgon 124 not out for Bexhill.
Other highlights: Milo Price 118 for Three Bridges 2nd XI; Redding Barnes 5-49 for Buxted Park; Charlie Hobden 5-17 for Glynde; Imran Khan 120 not out for Lewes Priory; Charlie Silvester 115 not out for Glynde 2nd XI; Thilina Perera 129 not out off 62 balls for Bognor Regis 2nd XI; Ed Barnes 122 for Roffey 3rd XI.