Iraq, fourth at the Athens 2004 Olympics, are looking to reach Rio 2016 with the tournament doubling as a qualifier for the Games.

They needed 36 minutes to break the deadlock against Yemen, and did so from the spot when Ali Faez Atia converted a penalty in the Group C clash.

The second arrived just three minutes later as Ali Hosni netted, with the result proving enough to send Iraq, winners of the tournament in 2013 when it was known as the Under-22 Championships, to the top of the table.

it could have been better for them, though, but Humam Tareq saw a penalty saved in the second-half.

"At the beginning, as with all opening games, the match was full of tension and at the beginning we were a little tense against a Yemen opponent who are not easy opponents," said Iraq coach Abdul Ghani Shahad.

"But I am satisfied with the performance and most importantly we scored and we won and we got the three points as that was the objective and the target for tonight.

“We played well in the second-half and going for the goal, but the turning point was the missed penalty and the performance after the penalty went down.

"We as the technical staff also changed some of the players to allow them to rest as some of the players are not at the top level to allow them to prepare for the next matches.”

The other match in the group saw South Korea, the London 2012 bronze medallists, who knocked out hosts Great Britain during that competition on penalties, see off Uzbekistan 2-1 at the same venue in the Qatar capital. 

Both of the Korean goals were scored by Pohang Steelers midfielder Moon Chang-jin, the first coming via a penalty on 20 minutes.

He found the target again three minutes into the second half, but Uzbekistan forced their way back into the contest thanks to a Dostonbek Khamdamov goal which ultimately proved to be just a consolation.

Uzbek hopes were not aided when Jamshid Boltaboev was sent-off in the second half with his side chasing the game.

Elsewhere, action also begun in Group B with Japan opening their account with a narrow 1-0 win over North Korea at Doha's Grand Hamad Stadium.

The Japanese came fourth in London after losing the bronze medal match 2-0 to the South Koreans, and claimed an early lead today as Naomichi Ueda struck after five minutes.

That proved to be enough, while in the other game in the group Saudi Arabia drew 1-1 with Thailand.

Mohammed Al-Saiari thought he head won it for the Saudis with a 71st minute effort, but the Thais struck back through Pinyo Inpinit seven minutes from time.

The Saudis were left to rue a Mustafa Al Bassas first-half penalty, which was tipped onto the bar by Thai keeper Somporn Yos.

The competition is due continue tomorrow with the first Group D matches, which will see Australia meet the United Arab Emirates and Vietnam square off with Jordan.

The top three countries will book their places at Rio 2016.