After finding themselves 3-0 down inside the opening 20 minutes, the Gulls pulled two goals back before half-time - and struck six more times in the second half to win 8-4!
Sibley (4) and Tuppen (3) led the fightback with Ryan Gray scoring on his debut. Sutcha Shepherd (2), Bradley Stokes and Thomas Young replied for Portchester.
Bailey Steele netted twice as Wicor Mill won 5-2 against North End Cosmos.
A Freddy Penfold hat-trick saw Southsea United win their opening Division 2 game 3-2 against AFC Bedhampton.
Freehouse battered Fleur De Lys 11-2 to claim their second successive win.
Sam Emeney netted three times as Seagulls Reserves defeated Fratton Trades in Division 3. Harry Grinyer was also on target in a second successive victory.
Tom Stevens’ treble helped Warren Wanderers pip Bransbury Wanderers 5-4. Sam Stone and Jordan Stevens also scored with Charlie Collins and Lewis Garfoot twice replying.
Dean Watson and Alfie Potter were on target for Waterlooville in a 2-1 victory against Falcon.
Mike Collins, Jordan Steele and sub Tom Webb netted as Portchester Royals drew 3-3 against Horndean United.
North End Lions beat Cross Keys Athletic 4-2 with goals from David Chester (2), Luke Donnelly and Michael Pilgrim.
Archie Drury fired a hat-trick in vain as AFC Solent were beaten 6-4 by a Fleur De Lys U23 side who are joint top of Division 4. Ty Moody also grabbed a consolation but Fleur won thanks to goals from James Bishop (2), Tom Webb (2), Louis Gaskin and Spencer Mayes.
Eastney keeper Josh Patterson turned in a man of the match display, including a penalty save, in his side’s Division 5 fixture with a Tamworth side top on goal difference.
But Tamworth, 5-1 up at the interval, still triumphed 7-2 with goals from Jack Boxall (3), Jack Holloway (2) and Jamal Welch (2). Saber Jamal and Mitchell Knowler replied.
Ricky Hemmings bagged four goals as second-placed AFC Fairfields pipped Al's Bar 5-4. Aaron Percey also netted with Joe Morley named as Fairfields’ man of the match.
Will Connole went nap as Freehouse A defeated new boys Southletico 6-3. Jason Shrewsbury also scored with Steve Mabbs, Chadley Cadman and Ryan Sirrs replying.
George Laskey netted twice as Horndean Hawks drubbed FC Fenix 7-0.Samuel Bruce, Jake Burfoot, Mitchell Coleman, Jason Green and Taylor Hammon also scored.
Nathan Craig and James Loveday were on target as Saturn Royale won 2-1 at AC.
AFC Fairfields Reserves bounced back from the previous week’s hammering to record a Division 6 victory.
After being thrashed 14-0 by Prospect Park Rangers, Fairfields won 4-2 against Spartan Athletic with goals from Dan Jafkins (2), Brad Wolfe and Chris Towle. Jamie Robinson and Dean Edwards replied.
Prospect Park Rangers lead the embryonic table after Harry Regan (2), Blake Bicknell and Jon Collington netted in a 4-1 win over Pelham Arms.
Harry Knight’s double helped Hatton Rovers defeat Padnell Rovers 6-3.
*Luke Baker was the top scorer among the first round ties in the Portsmouth Sunday Challenge Cup.
He struck EIGHT times as top flight Freehouse hammered fifth tier Fratton Trades A 19-0.
Alfie Fisher weighed in with a hat-trick with further goals arriving from Jack Davies (2), Brad Willett (2), Charlie Forrest, Jay Kane, Terry Boscoe and Matt Deans.
AFC Eastney Reserves came from behind to beat Milton Park Rangers. Ryan King put Rangers ahead but Eastney hit back in the second half with goals from Tyler Braddock and Bailey Williams.
George Caister was The Meon’s hat-trick hero as his side beat Cross Keys 7-3. Marvin Meal, Billy Musson, Charlie Musson and Callum Theobald also netted with Karol Serrani, Jack Spragg and Anton Dewing replying.
Compiled by Paul Oastler and Simon Carter