DOHA: Al Duhail on Wednesday were crowned Qatargas U-23 League champions despite losing their last match of the season.   Duhail's celebrartory mood took a dent after they lost to Al Sadd 0-1 in the match played at their home turf of Abdullah bin Khalifa Stadium.   Qatar's U-19 ace striker Hassan Ahmed settled a kennly fought contest in the 82nd minute.   Qatar Football Association Executive Comittee member Hai Balan and Hamad Ali, head of Pueblic Relations and Communication in Qatargas preceded over the league's closing ceremony where they handed over the trophy and medals to champions Al Duhail, runneres-up Al Arabi and third place Al Gharafa.   Al Duhail, with 17 wins, topped the overall standings, having accumulated 52 points in 22 matches.   Al Arabi, with 15 wins, finished the U-23 League in second place with 48 points.   Al Gharafa, with 12 wins, ended the season with 38 points to secure the third spot in the 12-team championship.   Al Rayyan, also with 38 points, finished in the fourth spot.   Al Markhiya (33 points), Al Sadd (32), Al Khor (30), Qatar SC (26), Al Sailiyah (26), Al Ahli (24), Al Kharaitiyat (19) and Umm Salal (13) completed the table.   In the last round of matches, Al Arabi beat Umm Salal 3-2, Al Gharafa edged Qatar SC 2-1, Al Ahli blanked Al Kharaitiyat 5-0, Al Sailiyah downed Al Khor 3-1 and Al Sadd beat Al Duhail 1-0.   Al Rayyan and Al Markhiya match ended in a 2-2 draw