Thailand U23 football team coach Issara Sritaro was left with mixed feelings after his men did just enough to reach the knockout stage of the Hangzhou Asian Games on Sunday night.
The Thais conceded a late equaliser for a 1-1 draw with Kuwait in their last Group E match to take third spot in the pool.
Defending champions South Korea defeated Bahrain 3-0 in the other match on the same night to finish first in the group with a perfect nine points from three outings.
Bahrain, Thailand and Kuwait all finished with two points each but Bahrain claimed the second place in the group for conceding one goal less than the Thais.
The Young War Elephants will now face hot favourites Iran in the last-16 round at Shangcheng Sports Centre Stadium tomorrow.
Issara expressed his joy at making the last-16 round but regretted his men's inability to hold on to their advantage.
"The first round is over and we have qualified for the next round, but we are a bit disappointed that we ended up drawing two matches that we should have won," said Issara, referring to the games against Bahrain and Kuwait.
"It's a pity that we could not finish off Kuwait. But the players have done their best to meet our target of qualifying for the last-16 stage.
"Our problem is that our backline is very vulnerable. We lost three players in the first half today [Sunday] and we don't know if these players will be able to play the next game or not."
Jakkrapong Sanmahung put the War Elephants ahead in the ninth minute with an angular shot that curved into the net.
Kuwait equalised a minute before the end of regulation time when Yousef Alhaqan guided a corner kick into the goal with a nifty header to steal a point for his team.