The 15-year-old Tanisha outplayed Jammu and Kashmir's Prinkle 6-1 6-4 in the final.
Ajay, who trains in a village in Gohana, Haryana faced stiff resistance from Krishna Hooda before winning 7-5 4-6 6-2 in the U-14 final.
"Today she (Tanisha) played what I want her to play. It was a high-quality affair. She had that extra aggression today in her strokes and that is what she needs to do consistently," said former India Davis Cupper Vishal Uppal, who trains Tanisha at DLTA.
The Under-14 girls singles title was won by Sandeepti Singh Rao, who outclassed Rutuja M Chaphalkar 6-1 6-1.
This year's junior National Championship was marred by allegations that over-aged players were competing in the tournament.
Many parents had signed a petition and presented it to AITA, demanding strict measures to check the menace.