DOHA: Duhail have launched the Qatargas U-23 League season by beating Al Markhiya 6-0 in a   lopsided game at Hamad bin Khalifa Stadium.     Sayed Issa and Hazem Ahmed netted a brace each. Duhail exhibited sheer quality as Qatar u-23 internationals Issa, Ahmed, Yassir and Al Ahraq dictated matters throughout the 90 minutes.     In another fixture, Ahmed Al Saadi was on target on three occasions as Al rayyan crushed Al Khuraitiyat 5-2 at Soud bin Abdulrahman Stadium.     In the third game of the day, Al Sadd and Qatar SC shared a 3-3 draw.     Jassim Al Shammari scored twice for Al Sadd (31, 34) while Ghassan Waheed added the third (61). For Qatar SC, Ali Awad scored twice (19, 53) and Ali Saeed added the (37).