The Reds conceded twice in the first half at Coopers Stadium before a Dylan McGowan own goal nine minutes from time ensured Gamba triumphed 3-0 in their Group H opener.

While Adelaide had some promising moments throughout the match and finished the game with more possession, passes and a great passing accuracy in their attacking half, the J.League visitors were far more clinical.

Gamba had 14 shots to Adelaide’s seven and led shots on target 5-1.

“They [Gamba] were using the ball a lot more efficiently, especially in the first 20 minutes,” Garuccio told Fox Sports.

“You could tell with their first goal they were very sharp and it was a good move, good cross and a great header.

“They were finding those spaces inside us a little bit. Their centre-backs were looking for that ball into the midfielder, which we weren’t compact enough in the middle.

“That let us down a little bit but they were very sharp and they are a good team and it showed tonight.”

Adelaide United 0 Gamba Osaka 3

While Adelaide was on the back-foot for large periods, wingers Garuccio and Nikola Mileusnic both created decent chances.

But Guillermo Amor’s side lacked a cutting edge in the front third - Sergio Cirio started as the Reds’ central striker - and when Yasuyuki Konno doubled Gamba’s lead in first-half stoppage-time, there was no way back for the hosts.

“I had a good chance in the box and maybe I could have cut back. We score that and we go 1-1 and you just never know how the game can go,” Garuccio said.

“That second goal on the stroke of half-time is a killer… it’s hard to come back from that.

“The second half was alright but I don’t think we created enough quality chances to really be in the game tonight.”

The 21-year-old added: “Me personally it took a little bit of adjusting that first 15-20 minutes I was very quiet but once you come into the game but once you find your feet it’s enjoyable.

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“It’s unbelievable to play against these players, in your career these are the sorts of players you want to be coming up against. It’s a great experience for all of us.”

Adelaide must turn their attention to Saturday night’s A-League clash with Melbourne Victory before they head to China next week to play Jiangsu Suning in the ACL.

Jiangsu defeated Jeju United 1-0 in Group H’s other match on Wednesday.