The margin of the defeat was significant, but Chu took some satisfaction from his team’s ceaseless efforts despite seeing their hopes of a place in the last eight slipping away.

“Even though we lost, I’m happy with the team because the players were fighting hard until the end,” Chu said. “We made one mistake and this is not good for us, because it made it easier for BG Pathum.

“They’re a good team, they’re strong and it’s not easy. If we want to try to attack then we give more space for them and make some mistakes again.”

Makoto Tegurmori’s side rarely looked troubled by their Hong Kong Premier League opponents and the game marked what is likely to be a disappointing end to the Asian Champions League career of all-time leading goalscorer Dejan Damjanovic.

The 41-year-old forward, scorer of a remarkable 42 goals in the continental competition, had few views of goal during the 90 minutes as the Kitchee midfield were often overwhelmed by a controlled performance from their Thai counterparts.

For all their superiority, though, it took until the 34th minute for BG Pathum to open the scoring and the opener came as a result of an error from goalkeeper Wang.

The goal came seconds after Kitchee had fashioned a rare opening at the other end when new signing Fernando, on as an early substitute for the injured Ruslan Mingazow, ballooned his effort over the bar.

Within seconds BG Pathum were in front. A hopeful ball forward from central midfielder Sarach Yooyen should have been cleared by Wang, but the goalkeeper dithered, caught in too many minds about what to do and allowing Worachit Kanitsribumphen to steal in behind to roll the ball home.

That goal threatened to open the floodgates with Teerasil firing over before BG Pathum doubled the lead. Ikhsan powered forward, leaving the Kitchee midfield in his wake and thumping an unstoppable strike into the top corner.

It could have been worse for Kitchee, but Sahart Pongsuwan’s cross from the left hit the far post rather than the head of Teerasil as BG Pathum showed the gap in class.

Chu introduced Alex Akande in an attempt to bolster his attacking options at the start of the second half, but BG Pathum were still relatively untroubled and as the game entered the final quarter the Thais went further ahead.

Brazilian substitute Diogo was granted too much time and space on the right and his pinpoint centre was steered in at the far post by Teerasil to give BG Pathum United an unassailable lead.

Defeat turned into a thrashing with three minutes remaining when Chatmongkol slipped the ball under the advancing Wang, taking BG Pathum United into the last eight for the first time and leaving Kitchee in no doubt about the gulf that exists to the continent’s leading teams.

“This is a very good experience for Kitchee and for the players, and if we have the chance to come again to the Asian Champions League then we have to play better,” Chu said. “It’s not easy, we cannot make any mistakes. We need to focus, concentrate and be ready.

“For me, we have learned a lot and being here is already a success. It was a good opportunity to learn something and we will learn later to play against other strong teams. This is football.”

Kitchee (4-3-2-1): Wang Zhenpeng; Roberto Junior (Alex Akande 46), Oliver Gerbig, Helio, Dani Cancela (Poon Pui Hin 76); Law Tsz Chun, Huang Yang (Cheng Chin Lung 83), Ruslan Mingazow (Fernando 16); Cleiton, Mikael; Dejan Damjanovic.

BG Pathum United (4-4-2): Kittipong Phoothawchuek; Santipharp Channgom (Jakkapahn Praisuwan 78), Irfan Fandi, Andres Tunez, Sahart Pongsuwan; Pathompon Charoenrattan (Jaroensak Wonggorn 66), Sarach Yooyen (Chatmongkol Tongkiri 66), Phitiwat Sookjitthammakul, Worachit Kanitsribumphen; Teerasil Dangda (Surachart Sareepim 78), Ikhsan Fandi (Diogo 58).

Goals: BG Pathum United: Worachit Kanitsribumphen 34, Ikhsan Fandi 39, Teerasil Dangda 68, Chatmongkol Tongkiri 87.

Bookings: Kitchee: Cleiton 9. BG Pathum United: Santipharp Channgom 45, Irfan Fandi 75.