Unseeded players, Lathika Prem Kumar of Tamil Nadu and Rajasthan's Udayan Bhakar, caused the biggest upsets in the girls' under-12 and boys' under-16 singles respectively, in the semi-finals of the Cricket Club of India (CCI) 6th Ramesh Desai Memorial All India Ranking National Tennis Championship 2012, played , at the (CCI) courts, Mumbai on Friday.