Unseeded Rohan Gajjar of India caused a major upset when he ousted top seed and compatriot Sunil Kumar Sipaeya 6-4, 6-4 to enter the men's singles semi-finals in the $6250 MSLTA-ITF Satellite tennis (first leg) tournament  at the Dr Ranade Tennis Centre in Mumbai on Thursday.

Giant-killer Mustafa Ghouse of India met his match when another unseeded player, Prima Simpatiaji of Indonesia, sidelined him at 7-6 (7-4), 6-1 in an hour and 12 minutes.

Indian tennis ace Vijay Amritraj's US-based son Prakash, who is seeded second, needed a second set tie-break to defeat sixth seed Vinod Sridhar of India 6-2, 7-6 (7-2) in an hour and 34 minutes while Daniel Kiernan came out triumphs in the battle of two qualifiers from Great Britain.

Kiernan subdued Richard Crabtree 7-6 (8-6), 6-3 in one hour and 47 minutes.

Gajjar played attacking tennis against the Delhi-based Sipaeya. He broke Sipaeya in the seventh game before serving out the set at 6-4.

In the second set too the calm and composed Mumbai lad, who served just one double-fault to his opponent's three, broke Sipaeya in the fifth game before serving out the match at 6-4. Gajjar served as many as nine aces while Sipaeya could manage even one.

Amritraj too had a good outing today. He first broke in the fifth and seventh games to win the set 6-2.

In the second set too, Amritraj broke his rival in the third game to lead 2-1. However, Sridhar fought back well with a break in the 10th game to level the game scores at 10-all before forcing the tie-break.

In the tie-break, Amritraj allowed his opponent just two points before wrapping up the match at 7-2.

Results (men's singles) quarter-finals: Rohan Gajjar (Ind) bt Sunil Kumar Sipaeya (Ind) 6-4, 6-4; Daniel Kiernan (GBR) bt Richard Crabtree (GBR) 7-6 (8-6), 6-3, Prakash Amritraj (Ind) bt Vinod Sridhar (Ind) 6-2, 7-6 (7-2); Prima Simpatiaji (Ina) bt Mustafa Ghouse (Ind) 7-6 (7-4), 6-1.

Doubles quarter-finals: Daniel Kiernan (GBR)/Ajay Ramaswami (Ind) bt Prakash Amritraj (Ind)/Stephen Amritraj (USA) 6-2, 6-1; Hendri-Susilo Pramono/Febi Widhiyanto (Ina) bt Sanchai Ratiwatana/Sonchat Ratiwatana (Tha) 6-4, 6-7 (4-7), 6-4; Saurabh Kohli/Rohan Gajjar (Ind) bt Vijay Kannan/ Saurav Panja (Ind) 6-2, 7-5; Manoj Mahadevan/Rishi Sridhar (Ind) bt Mustafa Ghouse/Vishal Uppal (Ind) 6-2, 3-6, 6-3.