Iraq topped the group with five points but could easily have lost the game after surviving a relentless wave of Omani pressure that could have cost them a place in the last eight.

The result sparked scenes of jubilation in one section of the near-empty Supachalasai stadium, where about 200 rejoicing flag-waving Iraqis sang long after the final whistle.

"Even if we didn't play well, we had to do what was necessary to qualify," Iraq's Brazilian coach Jorvan Vieira told a news conference.

"It was a very distressing match. It was like a final, it was a very complicated game."

Oman needed victory to stand any chance of going through and were on the attack from the outset.

They spurned countless chances but could have won the game a minute from time when Younis Al Mushaifri's header whistled past the post with the keeper beaten.

Oman were lifted by about 250 vociferous fans dressed in national flags and honchos, who danced in the streaming rain with Arabic music blasting through a megaphone.

Oman had good early chance after eight minutes when Badar Mubarak's shot from outside the area forced a save from Noor Sabri.

They almost went ahead on 27 minutes when Ismail Al Ajmi latched on to a deep cross and fired into a crowd of players.

Oman were frustrated near halftime when Fawzi Bashir chased a long ball and blasted wide from a tight angle.

Oman piled on the pressure after the break and had a chance on 52 minutes when Ali Ajmi's looping header dipped just over the bar.

Iraq could have taken the lead on the hour mark against the run of play when Mahdi Karim beat two men to deliver an inch-perfect cross to the onrushing Younis Mahmood, who headed wide from close range.

Oman continued to press the Iraqis and almost went ahead two minutes later when Ahmed Hadid's long range free kick bound for the top corner was acrobatically tipped over by Sabri.

"I'm very disappointed, we had a lot of chances to score and qualify," said Oman's Argentine coach Gabriel Calderon.

"We only needed to score a goal. I'm happy with the performance and happy with the spirit of my players."

Iraq will play Group B runners-up Vietnam in Bangkok on Saturday.