Coming into the evening the Mariners were in a positive position to progress from to the competition's knockout phase as they led Group F with six points.
But despite creating a series of first-half chances and some good second-half opportunities, Central Coast never managed to break down FC Seoul’s defence.
And, when Kim Jin-kyu lobbed it in from the left-hand channel as time ticked off the clock, Hutchinson misdirected the ball into the Mariners own net, sending the visitors, and their bench, into delirium.
Mariners’ goalkeeper Liam Reddy was best-on-ground for the hosts throughout the night, pulling off a string of acrobatic saves with both his feet and hands but his teammates, including Matt Simon, Josh Rose and Bernie Ibini couldn’t find the net despite some good penetration from players such as Mile Sterjovski.
The A-League champions now face two stern tests across two competitions, starting with Saturday's cut-throat final against Adelaide United before Central Coast head to Japan for their final Group F clash against Sanfrecce Hiroshima next Wednesday.
Having beaten Sanfrecce in the competition already, the Mariners have the head-to-head advantage so conceivably a draw could see the Mariners progress should FC Seoul dispatch Beijing, but a win would ensure progress.
"Very disappointed with the result obviously," Moss said.
"The first thing we did in there (the dressing room) was put our arm around Hutch and make sure he stayed positive, but he is a great leader.
"In there the first thing he is talking about is Saturday’s semi-final and getting back on the horse which is a blessing for us after a result like that in the dying minutes."
A tactical change focusing on blunting the visitor’s attack was identified as important for the side pre-match.
"Playing the extra number in the backline with Monty (Nick Montgomery) dropping out of midfield was really important tonight because of their forward runs. They play a narrow three with their fullbacks getting over the top so in our analysis of them we thought that was important.
"Some nights things come off for you, other nights they don’t."
"I felt we dominated first half and we had to take one of those chances and if we did that (it’s a) different ball game.
"The only time they threatened early was going long and direct and in transition when we tried to force access through the middle, which we spoke about before the game.
"So there were aspects of the game-plan that we probably strayed from a little bit.
Moss felt the Mariners were in the driver’s seat at times in the match.
"I thought late on we were hanging on and I thought maybe with the injection of Bernie (Ibini) and Dukey (Mitchell Duke) and (Glen) Trifiro in midfield I thought we might have caught them on the break which we did a couple of times but we just couldn’t execute (the opportunities)."
The Mariners will face a buoyant Sanfrecce Hiroshima next week in Japan after they fought back from 2-0 down in the second half to claim a point in China against Beijing Guoan on Wednesday night in the other Group F encounter.
Like Sanfrecce and Beijing the Mariners are on six points, with FC Seoul topping the group on eight points.
