In a statement, United said the Spaniard advised chairman Greg Griffin today he had decided “to not continue in his position as senior coach”.

The statement said the decision was “much to Griffin’s and the club’s sadness and disappointment, but [it] is of course accepted”.

Amor joined the Reds as Technical Director for the 2014-15 season before taking over as coach from Josep Gombau in 2015, and guiding the club to both the premiership and championship in his first season at the helm.

However United has struggled thereafter, falling to ninth on the ladder by the end of the 2016-17 season.

“The Club would like to thank Guillermo for his diligence and hard work during his time with us, as well as guiding us to our long-awaited Championship in front of a packed Adelaide Oval last year,” United’s statement read.

“Adelaide United has already commenced a recruitment process to appoint a new Head Coach and will ensure a new coaching personnel are appointed by mid-June, in time for the Club’s pre-season preparations.”

It’s likely several players will also head for the exit door, after the Reds were knocked out of the Asian Champions League with a 1-0 loss to China’s Jiangsu Suning last night.

Amor wouldn’t comment on his future after the Reds failed to advance in the ACL fixture, needing to win and also for Jeju United not to gain any points from a simultaneous fixture.

But coupled with their defeat, South Korea’s Jeju downed Gamba Osaka 2-0 to advance to the round of 16.

Adelaide United and Jiangsu FC players at Hindmarsh Stadium last night, where the Reds’ ACL campaign ended. Photo: David Mariuz / AAP

Adelaide finished third in the group, some five points shy of Jeju, after an Asian campaign which returned one win, three draws and three losses.

Before 6797 spectators at Coopers Stadium, the Reds bossed a second-string Jiangsu – the visitors left their stars at home, having already sewn up top spot in the group.

But a wayward Adelaide couldn’t land a punch despite basking in 71 per cent possession and recording 20 shots to six – including nine to one in the opening half.

The Reds fluffed a succession of chances – Riley McGree, Nikola Mileusnic, Sergio Cirio, Baba Diawara and Kim Jae-sung all sprayed shots wide, while Diawara also hit the post with a header.

McGree also had an early gilt-edged chance denied when, just five metres from goal but on his non-preferred right foot, his shot was superbly saved by Jiansgu goalkeeper Jiang Hao.

The visitors, with imports Alex Teixeira and Roger Martinez at home and missing Brazilian international Ramires because of suspension, relied exclusively on counter-attacks.

And, on 81 minutes, they made Adelaide pay for their lack of finishing polish – a common theme in the Reds’ lousy domestic campaign as well – when Ji Xiang scored with a sweet left-footer from 15 metres out.

Adelaide’s focus now turns to signings – they have 16 players about to fall off contract.

Captain Eugene Galekovic made what appeared to be an emotional farewell to Adelaide fans after the loss. He headlines a list of players expected to depart Adelaide which includes Marcelo Carrusca, Dylan McGowan, Sergio Cirio, Iacopo La Rocca and imports Baba Diawara and Kim Jae-sung.

Amor would not buy into media questions about his tenure at the time.

“Here in this moment, no,” Amor said.

“I don’t know if it’s the next hours, the next days, tomorrow, after tomorrow – it’s possible. But now, here, no.”

But the Barcelona great said he couldn’t criticise his players for their display against Jiangsu.

“We play very well, it’s impossible to say something negative about our game,” he said.

Galekovic is considering offers from A-League rivals with Adelaide already announcing the signing of his one-time goalkeeping understudy Paul Izzo from Central Coast.

Attacker Cirio is also tipped to sign with the Mariners, brilliant midfielder Carrusca is weighing up offers, while defender McGowan is expected to soon announce his departure for an as-yet unknown overseas club.

-with AAP