Seven days after beating Gwynedd League leaders Trearddur Bay Bulls and ending their perfect seven-game 100% record, Bontnewydd were brought crashing back down to earth when they lost 3-2 at home to struggling Llanystumdwy.
It was quite a result for the visitors, whose goals came from Guto Roberts (pen), Mark Godfrey and Louis Galvin, while their keeper, recent signing Ben Jones, kept out a penalty and made some other stunning saves.
Josh Williams and Morgan Roberts were on target for Bont.
Bangor 1876 made it five straight league wins with a hard-fought 4-2 verdict at Talysarn Celts.
Glyn Tomos put the Celts in front from a long range strike in the ninth minute, but Dylan Williams levelled on 31 and a Les Davies free kick made it 2-1 to 1876 just before half time.
Four minutes into the second half, Jamie Petrie converted his sixth penalty this term for the Treborth side and on 61 minutes the same player struck again with his 14th goal overall of the campaign.
Talysarn never gave in and hit back with a deserved second goal from Gerwyn Williams.
A reported 370 spectators were at Gloddfa Glai, Talysarn – a new ground record.
Menai Bridge Tigers defeated Ogwen Tigers 3-1, Callum Davidson (2) and Dave Baston on the mark for the winners, Thomas Evans responding.
Steve Jones and Dylan Sion Jones found the net for Nefyn United in a 2-1 victory against Llangoed, Craig Jones scoring for the Anglesey side.
Postponed due to no referees: Glantraeth v Llannerchymedd, Trearddur Bay Bulls v Caergybi.
Report: Waunfawr 2 Bro Goronwy 0
The Beganifs made the most of their first half dominance, creating plenty of opportunities with the forward trio made up of Carwyn Paramore, Shaun Roberts and Meurig Parry doing most of the damage, writes Paul Scholes.
Bro keeper Jonny Sweetser-Hawkes excelled in tipping over an Osian Glyn free kick before the hosts were awarded a controversial penalty for an alleged push after 14 minutes.
Dylan Hughes failed to take advantage from the spot, Sweetser-Hawkes flinging himself to his right to palm the ball away.
The deadlock was broken on 31 minutes.
Paramore combined with Parry, who made light work of getting behind Bro’s back-line to finish from close range.
The visitors would have settled for going into the break only a goal down and confident of turning the match around but in stoppage time fell to a sucker punch.
Hughes connected well enough with his volley to send the ball past the stopper and soaring into the net for a 2-0 half time scoreline.
Bro were a transformed team after the break, but still lacked the final bit of quality as Waunfawr held them at bay.
However, the hosts could count themselves lucky not to be in a closer match only two minutes after the restart.
Iwan Williams reached the ball before the glovesman only to be hauled down, but John Gould made amends by saving the spot kick via his dangling legs down the middle of the goal.
Bro’s Sam Roberts should have set up a tense finale but could not keep his header down and Shaun Roberts could have put the game to bed but sent his strike high.
One last punt upfield nearly brought a goal for the visitors, Connor Jones flicked header all ends looking like to be heading into the net before Gould somehow reached out to tip to safety to seal the hosts a satisfying victory.