The Boyds lost in the pairs final last year to former Black Jacks Genevieve Baildon and Jan Shirley.
Mandy, who recently returned from a Black Jacks campaign at World Bowls in Adelaide, won a silver medal in the women's triples with teammates Lisa White and Jan Khan.
Angela, 26, an early childhood teacher in Napier, is part of the New Zealand Talent Development Squad and also showed her prowess in making the last eight of the women's Open singles this week, bowing out 21-18 to Anna Davis of Palmerston North.
The women's pairs is an opportune time for the Bay sisters not only to compete, something they have been doing since they were youngsters here, but also spend quality family time together during the Christmas holidays with mother Lynda arriving in time on Thursday to watch her daughters' semifinal, although dad Doug was unable to make it.
"We were always two to three behind and then we caught up, and then they went up two to three more and then we caught up, so we were always fighting to get on top of them," Mandy said, lauding Keith and Matthews and emphasising the former won the Open women's singles title last year before going on to clinch the World Championship bragging rights, too.
"It wasn't because they were more experienced. It was windy and the greens were running fast so a couple of our shots didn't come off. In bowls, you always need a little bit of luck."
Mandy, who belongs to the Johnsonville Bowling Club now, does not anticipate living in the capital after finishing her studies this year.
"I'm looking for some new adventure somewhere else but I've no idea where right now," she said, before adding the Bay was her favourite place.
Angela said the sisters had stuck to their game plan in the pairs final.
"We were hoping to do it [win] this year but it didn't happen but, hey, there's always next year."
Angela was delighted to make the women's Open single quarter-finals after making the last 16 once before but struggling to pin down which year.
Mandy made a first-round exit in the singles.
"There are some tough teams in the fours but we're backing ourselves to win," Angela said.
In the men's pairs final, Ali Forsyth/ Matthew Gallop (composite) comfortably trounced Rob Ashton/ Barclay Lee (composite) 15-9.
In the women's singles final, Val McEldowney, of New Plymouth, pipped Reen Stratford, of Birkenhead club, 21-17 while in the men's singles final Shaun Scott (North East Valley) crushed Danny Delany (Onehunga) 21-10.