Mansi is the second seed for the under-10 girls' singles. She will also play in the doubles in the same age group as well as the under-12 singles' and doubles.
The Taradale Primary School Year 5 pupil recently won the Hawke's Bay Primary Schools girls title and earlier this month won the under-16 girls' singles title and was in a beaten doubles combination in the same at group at the Waipukurau Junior Open.
Mayank, who will turn 8 on December 27, will be the third seed in the under-10 boys singles. The Year 3 student will also play in the doubles in the same age group.
Their father Suni, who hails from India and is an inventory manager at Tamatea Pak'nSave, is rapt with his right handed children's progress.
"They only took tennis up because we live near the Greendale courts and happened to walk past the courts one day. Mansi liked what she saw and told us she wanted to take it up and so did Mayank. There are no courts back home where I'm from and I had never played before. I'm more into chess and cricket, and Puspa played volleyball," Suni explained.
"If we forget to take them to trainings they are quick to remind us they should be there. Tennis is the No 1 sport for both of them ... we're happy to let them go for it and can't wait to see how far they can get," he added.
"Serena Williams is my favourite female player and Roger Federer my favourite male player. I want to be a professional like them in the future I'm grateful for the work my coach Luke [Donovan] has done and training with the boys at the club has certainly helped too," Mansi, who is also into athletics and kapa haka, said.
The dreadlocked Mayank also hopes to be a professional in the future and heaped kudos on his coach Jac Wardrope. Mayank is also into football, basketball, running and cricket.
The pair were thrilled with what their powerful forehands can deliver but, like most youngsters their age, were quick to point out there was still plenty of room for improvement with their respective backhands.
Mansi is delighted with the support they receive from their school principal, Hawke's Bay premier club rugby referee Marty Hantz.
"He plays tennis with us as often as he can."
The Giri siblings, who are sponsored by their club, said it will only be a short period of time before their 3-year-old sister Vanisha makes a similar impact on the Bay tennis scene.
"She's into dancing so she will have pretty good footwork," Mayank said.
Another Hawke's Bay brother-sister combination expected to perform well in the open are the Hawke's Bay Lawn pair of River and India Apatu. River is the top seed in the under-14 singles while India is the second seed in the under-12s.
River proved he is peaking at the right time with a recent A reserve men's grade interclub singles win against experienced Greendale campaigner Simon Cowan. Few juniors have the necessary patience levels or skills to out-fox Cowan.
The open has attracted 150 players, including 45 from Australia. Singles and doubles matches will be played in all age groups from under-10 to under-18.
Both the Greendale and Hawke's Bay Lawn clubs will be used.