2008 AFC Champions League knockout stage
The 2008 AFC Champions League knockout stage was played from 17 September to 12 November 2008. A total of eight teams competed in the knockout stage to decide the champions of the 2008 AFC Champions League.
Qualified teams
The knockout stage involved seven teams which qualified as winners in the group stage, plus defending champions Urawa Red Diamonds.| Zone | Group | Winners |
| West Asia | A | Bunyodkor |
| West Asia | B | Saipa |
| West Asia | C | Al-Karamah |
| West Asia | D | Al Qadsia |
| East Asia | E | Adelaide United |
| East Asia | F | Kashima Antlers |
| East Asia | G | Gamba Osaka |
| East Asia | Urawa Red DiamondsTH |
Bracket
Quarter-finals
The first leg matches were played on 17 September, and the second leg matches were played on 24 September 2008.
Matches
Adelaide United won 2–1 on aggregate.----
Bunyodkor won 7–3 on aggregate.
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Gamba Osaka won 4–1 on aggregate.
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''Urawa Red Diamonds won 4–3 on aggregate.''
Semi-finals
The first leg matches were played on 8 October, and the second leg matches were played on 22 October 2008.
Matches
Gamba Osaka won 4–2 on aggregate.----
''Adelaide United won 3–1 on aggregate.''
Final
The first and second legs of the final were scheduled to be played on 5 November and 12 November 2008, respectively.Matches
Gamba Osaka won 5–0 on aggregate.