A small group of fans have made the long journey north from Port Talbot, and they brave extremely wet underfoot conditions to stand behind the goal their team are attacking in the first half.
The game has attracted a large crowd to Maes Meurig, with the hosts doing an excellent job off the field of organising their big day.
There are dug outs on opposite sides of the pitch, but the Port Talbot management team and substitutes make use of the terracing next to the home bench, presumably because a fourth official is appointed at this stage of the competition.
It is probably fair to say the ground is not in one of Anglesey's most scenic locations, although there are distant views of the Snowdonia hills to enjoy.
The hosts look to up against it as Martin Rose heads Port Talbot into a 12th minute lead, but the ground erupts just a minute later, Mark Evans providing the cross for Paul Tilbury to head home an immediate equaliser.
Unfortunately for the hosts that is pretty much as good as it gets, and a needless handball offence from Stephen Sinclair allows Martin Rose to score his second goal on 34 minutes from the penalty spot.
Port Talbot look to be in complete control at the interval, Lee John putting Luke Bowen through for a 40th minute strike to give a 3-1 scoreline.
Although Port Talbot cannot totally kill the game off after the interval, Gwalchmai struggle to create any clear opportunities, and the chances of an upset seem long gone even before the 82nd minute dismissal of Stephen Sinclair, the home defender getting involved in a spot of nonsense with visiting keeper Lee Kendall, and seeing red for a little kick out.
Port Talbot finally wrap up the scoring for a 4-1 victory in the 90th minute, Nicky Holland's cross allowed to run across the area, where skipper Liam McCreesh had space to apply the finish.
