Joe Montemurro calls out error in substitutions following Steph Catley's early exit with concussion

Matildas coach Joe Montemurro has called on the Asian Football Confederation to be more cautious with recording substitutions after Australia were left scrambling due to an off-field mishap.

The Matildas fell short in their quest to top group A in the Asian Cup and could be without gun defender Steph Catley for the quarter-final, in which they will meet either China or North Korea.

Australia had to beat South Korea in Sydney on Sunday night to finish on top of group A.

They could only muster a 3-3 draw.

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Alanna Kennedy drew the Matildas level with South Korea when she scored her second goal of the game in the dying seconds of stoppage time, thundering the ball into the back of the net after a messy passage of play.

Catley has been an integral force for the Matildas at the Asian Cup, orchestrating the defensive line-up throughout each game.

But as she attempted to block a breakaway run by South Korea early in Sunday night's match, she was struck in the head by a ball just outside the box.

Catley immediately fell to the ground at Stadium Australia and the crowd went silent.

Medics were quick to run out to aid the Matildas star.

"Immediately this is a huge concern," Andy Harper said on Paramount+.

"This is a really, really concerning sign," Matildas great Grace Gill added.

Catley managed to walk herself to the goal line alongside medics, where she underwent further concussion testing.

She returned to the field minutes later, but in the 17th minute she finished up for the night.

Montemurro had already called for Courtney Nevin to prepare in case Catley was unable to see out the match and Nevin was duly substituted on as her replacement.

However, Montemurro was left frustrated later in the match as the substitution of Nevin was not correctly recorded.

"Steph was taken off for a concussion issue and there was a lot of confusion with that concussion sub," Montemurro told reporters post-match.

"It wasn't registered, so then we couldn't make the relative subs that we need to (later).

"I think that is something that the AFC have to be a bit cautious about. It wasn't registered on the iPad ... so we just had to readjust things then in the end. They gave us the concussion sub but it was too late. South Korea used it."

Catley's concussion was a major blow for the Matildas, who were already without Hayley Raso for the match against South Korea due to concussion symptoms.

Shortly after Catley's first medical exit, South Korea's Mun Eunju fired the ball past Mackenzie Arnold with ease to open the scoring.

South Korea's lead did not last long, though, with Kennedy sending a beautiful header into the back of the net in the 32nd minute to level the scores.

Sam Kerr found Australia's second goal of the first half in the final minute of stoppage time, nailing a beautiful cross into the back of the net.

Once the teams returned for the final half of the group stage, South Korea unleashed a roaring attacking raid.

Kim Shinji was the second Korean star to get past Arnold, defeating Australia's World Cup goalkeeper via a penalty.

Her teammate Kang Chae-rim followed just three minutes later, stunning Arnold as she took a late shot at goal.

Arnold was in disbelief as Chae-rim scored Korea's third goal as it appeared the ball would be a simple cross to the opposite side of the box.

Harper was stunned that Korea had chosen to go for goal instead of playing it safe.

"Many thought that Korea would sit back after equalising, as a draw for them was enough to go through, but the substitutes have combined again," he said.

Montemurro conceded the Matildas needed to be wiser and stick together.

"There are times when you just have to be smart and slow it down," he said.

"We rushed, we got caught twice ... That's going to hurt us. It did hurt us."