Olympic bronze medallist Saina took 36 minutes to brush aside Mingtian Fu of Indonesia 21-16 21-9 in the women's singles at the SK Handball Stadium here.
World number three Saina will next take on Lin Han of China, a player against whom she has a 2-0 record. Han beat Tzu Ying Tai of Chinese Taipei 21-16 21-16 in another match.
Olympic quarterfinalist Kashyap played his heart out and was one game up but seventh seed Yun Hu of Hong Kong came from behind to notch up a 16-21 21-13 21-17 victory over the Indian in the men's singles.
World number 17 Sindhu also failed to cross the second round after she went down 19-21 13-21 to Thailand's Porntip Buranaprasertsuk in a 31-minute women's singles match.
Sindhu had beaten the Thai girl twice in the past but she was not third time lucky as the world number 13 set up a clash with Korea's Ji Hyun Sung, who stunned seventh seed Chinese Yanjiao Jiang 21-10 21-17.
Saina dominated the nets and used her smashes to good use against Mingtian. The Indian slowly opened up a 3-1 lead in the first game and kept widening the gap to pocket the game.
The second game was no different as Saina once again moved to 6-2 early on and then stretched her lead by reeling off consecutive points at will to make a smooth entry into the quarterfinals.
