A rare error from United's veteran goalkeeper was all it took for the visitors' perfect record in the ACL to come to an end
Adelaide United's perfect start to their AFC Champions League campaign came to an end after a 1-0 loss to Pohang Steelers in Korea on Tuesday.
The A-League side remained compact defensively, but an uncharacteristic error from Eugene Galekovic allowed Kim Dae-Ho to scramble home what proved to be the winner in the 69th minute.
Adelaide remain top of Group E despite the loss, level on six points with Pohang, while Bunyodkor and Gamba Osaka are third and fourth respectively.
The hosts dominated a dour first half in windy conditions at Steelyard Stadium and fired the first shot on target inside four minutes.
After receiving a pass from Park Hee-Chul, Ianis Zicu - a constant threat - forced Galekovic into a regulation save from the edge of the area.
Pohang again went close in the eighth minute thanks to some delightful play from Zicu.
The Romanian striker held off two markers before releasing Park with a superb back-heel, and the midfielder squared for Ko Mu-Yeol, who curled a shot well over the bar.
Adelaide striker Bruce Djite was largely isolated up front in a 4-1-4-1 formation - one that has held the Reds in good stead throughout the group stage.
The visitors were remaining sturdy in defence, although Derek Asamoah and Zicu looked threatening.
The speedy Asamoah caused left-back Cassio problems throughout the first half, and was denied a penalty in the 20th minute after going down under light contact from the Brazilian.
Pohang kept pushing for an opener and Kim missed a good chance from a corner when he failed to make enough contact with his header.
With John Kosmina in Canberra doing his 'A' coaching licence course, assistant coach Luciano Trani - formally taking the reins for the Asian Champions League campaign - was in full control.
He was forced into a substitution just before half-time when attacker Dario Vidosic came off with what appeared to be a hamstring injury and was replaced by Fabian Barbiero.
The second half was much the same as the first, and Zicu went close when he headed a Hwang Jin-Sung set-piece over the bar on 66 minutes.
The hosts went ahead just two minutes later when Kim capitalised on a Galekovic error to strike.
Galekovic looked to have a Hwang free-kick covered only to fumble the shot, with Kim on hand to scramble home despite Djite's efforts to clear off the line.
Sergio van Dijk came on as Adelaide looked for an equaliser, but they rarely troubled Steelers shot-stopper Kim Da-Sol.
Zicu, who has struck four K-League goals this campaign, fired a 25-yard shot narrowly wide in the 83rd minute.
A late Cassio set-piece came to nothing as the Steelers hung on for an important three points, ending Adelaide's excellent start in Group E.