Legendary sprinter P.T. Usha could hardly stop smiling as her trainee Tintu Luka hung on to win the 800 metres gold in the third leg of the Asian Grand Prix athletics at the Nehru Stadium here Wednesday.

Luka looked out of breath over the home stretch and her initial 50-metre lead helped her to stave off the challenge as she finished in two minutes, 03.67 seconds, ahead of Kazhakhstan's Margarita Matsko (2:04.42) and Sushma Devi (2:04.42) of India.