A marauding South Korean front line lead by Kim Dae-won has provided the Olyroos with a "great learning curve" after their 2-0 AFC U-23 Championship semi-final loss, coach Graham Arnold says.

Kim's 56th minute tap-in and Lee Dong-gyeong's powerful effort from distance in the 76th minute sealed Olympic qualification for a clinical South Korea at Bangkok's Thammasat Stadium on Wednesday night.

Australia can still qualify for Tokyo if they overcome Uzbekistan, who were beaten 1-0 by Saudi Arabia in the other last-four clash, in the third-place playoff on Saturday.

Olyroos coach Graham Arnold praised South Korea's physical power and speed, saying the country's investment in young players is showing.

"Obviously it is disappointing tonight, but you have to take your hat off to South Korea. South Korea played very well, and we were beaten by a better team tonight," he said.

The coach said his young side had had an important experience in becoming the first-ever Australian U-23 side to make the semi-finals at an Asian tournament.

"It was a great learning curve for them, a great lesson for them and we move forward," Arnold added.

After an evenly matched and at times drab first half, the White Wolves began to turn the screws on their opponents, and broke the deadlock with midfielder Kim's fine poacher's goal in the 56th minute.

Lee You-hyeon's low effort from the right fizzed past an outstretched Glover and struck the left post, with the unmarked Kim waiting to tap into an open goal.

The strike lifted South Korea and shortly after, defender Jeong escaped from a congested 18-yard box to find himself one-on-one with Glover, only to thrash a panicked shot skywards.

South Korea then deservedly doubled their lead in the 76th minute after some deft footwork from substitute Lee Dong-gyeong.

The midfielder received the ball on the edge of the area and cut inside defender Dylan Ryan before drilling a low, left-footed effort off the post into the net, sparking wild celebrations in the mainly South Korean crowd.

Australia did try to break out but a relentless South Korea swarmed over quarter-final hero Al Hassan Toure and fellow forwards Trent Buhagiar, Jacob Italiano and Reno Piscopo.

Arnold is still confident the Olyroos can secure their first Olympic appearance in 12 years by beating Uzbekistan in their clash, which starts at 11.30pm (AEDT) on Saturday.

"We have got to show, and we will show, the Aussie spirit of fighting," he said.

"I said to the boys after the game 'great effort, we did well in patches, but that game is over now, there's nothing you can do about that. South Korea were the better team on the night. It is all now about what's in front of us and that's Uzbekistan on Saturday and winning that game'."