Barry Town United went down 3-0 at Briton Ferry Llansawel in the Adran Premier on Sunday.
Amelia Herbert was sent off for two yellow cards, leaving them with just one win in five league games under manager James Fishlock.
The visitors, looking to respond to last weekend's shock Welsh Cup exit, opted for two changes with Beca Thomas and Amelia Herbert replacing Ellie Preece and Keira Harris.
Barry almost took an early lead when Sienna Stone broke clear before her effort went wide.
Not long after, the hosts went ahead on the quarter-hour mark when Brooke Llewellyn beat a goalmouth scramble from a corner kick and struck past keeper Molly Arnesen.
The visitors pressed for an equaliser with India Shanahan forcing Courtney Young into making a fine save from Thomas' cross.
But just before half time, a debatable high foot saw Herbert being sent off for her second booking in five minutes, setting the scene for another tough afternoon.
Six minutes after the break, Ferry captain Lucy Powell punished a Barry defensive error and struck into a half empty net to double their lead.
A string of fine saves from Arnesen kept the hosts from inflicting further damage, while at the other end, Gunney had an effort blocked by Young in the closing stages.
But finally in stoppage time, Barry were again caught as Anya Grunewald played in Jade Crofts to slot home Ferry's third and wrap up the points.
Barry remain seventh in the table ahead of next Sunday's visit to The New Saints, who held Cardiff City to a 3-3 draw.
And that result allowed to Wrexham to take top spot for the first time this season following their 4-2 win over Swansea City.
Pontypridd United remain rooted to the foot of the table following their 2-1 defeat at Aberystwyth.
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