Kilani took a quick lead against Agarwal in the opening set as the former gained control to take a 4-1 lead.
Agarwal made it 4-2 by breaking Kilani's serve but, in the very next game, failed to hold his own.
Down 2-5, Agarwal once again succeeded in breaking Kilani making it 3-5.
The Tunisian made no mistake, racing to a 6-3 lead.
In the second, Agarwal played all out, exploiting all empty areas on the opponent's court as he looked a different player.
A confident-looking Agarwal rallied to win the second set 6-2 while in the decider, there was drama in store with the second seed being 3-5 down.
But the U-18 champion (at Fenesta Delhi 2012) bounced back to win the final set 7-5.
More From This Section
Agarwal will face Shao Chi Yang, seeded seventh from Chinese Taipei in the quarters tomorrow.
Results (India, if not mentioned)
Boys: Skander Mansouri (TUN)(1) b Robbie Ridout (GBR) 6-0, 6-3; Nino Serdarusic (CRO) bt Shaikh Abdullah 6-3, 3-6, 6-0; Chin Chun Tang (TPE)(3) b Patrik Niklas Salminen (FIN) 6-4, 6-3; Teradon Tortrakul (THA)(8) b Wei De Lin (TPE) 6-1, 6-2; Djurabeck Karimov (UZB)(6) b Dhruv Pal 6-2, 6-2; Mehdi Abid (TUN)(4) bt Ho Jun Lee (TPE) 7-5, 6-1; Shao Chi Yang (TPE)(7) bt Eero Vasa (FIN) 6-3, 3-6, 6-3; Rishabh Agarwal (2) b Majed Kilani (TUN) 3-6, 6-2, 7-5.
Girls: Pranjala Yadlapalli b Fang Hsien Wu (TPE) 6-1, 6-1; Thanthita Suetrong (THA)(5) b Dhruti Tatachar Veenugopal 7-5, 4-6, 6-4; Simran Kaur Sethi (4) b Pei Wen Kao (TPE) 6-2, 6-3; Raveena Kingsley (USA) b Chang Ya Ting (TPE)(6) 6-4, 6-3; Ksenija Sharifova (RUS) b Anastasia Prokopenko (UKR) 6-4, 6-1; Snehadevi Reddy (7) b Ekaterina Popova (RUS) 7-5, 6-2; Riya Bhatia (8) b Chanikarn Silakul (THA) 6-3, 6-4.
