Debutants Tajikistan struck twice late on to beat Lebanon 2-1 and reach the Asian Cup knockout rounds on Monday but China's hopes are hanging by a thread after defeat to Qatar.

The top two from each of the six groups qualify automatically but going with them are the four best third-placed teams, adding an extra layer of intrigue.

Qatar finished with a perfect nine points, with Tajikistan on four, China two and Lebanon one – and on their way home.

Tajikistan thought they had taken the lead on the cusp of half-time but the referee ruled the goal out for the tightest of offsides.

Their misery was compounded almost immediately after the restart when Bangkok United forward Bassel Jradi arched in a delicious strike from the edge of the area to put Lebanon ahead.

But Lebanon soon had a man sent off when a VAR check upgraded Kassem El Zein's yellow card for a studs-up challenge to a red.

With a man advantage, Tajikistan once again thought they had scored, but Alisher Dzhalilov's goal was scratched off again by VAR for a cruelly slender offside.

Parvizdzhon Umarbaev deservedly levelled in the 80th minute with a delicious, curling free-kick.

As things stood the Tajiks were going through, but they continued to push for a winner and got it in the second of 16 minutes of injury time through Nuriddin Khamrokulov's delicate backwards header.

In the other game, Qatar defeated a blunt China 1-0 and the Chinese must now hope for a miracle – that their two points is enough to qualify as one of the four best third-placed teams.

If China do go out they can have no complaints – they failed to score in any of their three matches and could not beat or even draw with a much-changed Qatar side who had already topped Group A.

Hassan Al-Haydos's 66th-minute wonder goal gave the hosts and holders victory, and edged China towards the trapdoor. (AFP)