Paige Schofield hit three centuries in two days as Sussex Under-17 girls booked their place in the national Twenty20 finals.
Schofield blasted 356 runs in four matches as Sussex won all three regional matches before triumphing in the final.
The young all-rounder also took 3-14 in one match.
In the first match against Oxfordshire, Sussex scored 176 for three off their 20 overs with Scholfield making 105 not out off 66 balls, including 16 fours and two sixes.
Sussex then beat Essex before Schofield went run-crazy again, hitting an unbeaten 102 against Kent with 16 boundaries.
In the final against Essex, Schofield hit 134 not out and with fellow opener Izzy Collis, who made an unbeaten 54, put on 206 for the first wicket.
Sussex won comfortably and, along with the county's under-15 side, will play in the national final at Leamington Spa later this month.
Director of Sussex Women’s Cricket, Charlotte Burton said: “Paige Schofield’s three hundreds is something I have never heard of being been done in women’s T20 cricket, especially over two days, and is an incredible achievement.
"I know the players will look to win all the T20 trophies and I know each squad has the ability to do it.”