user: Question: The match against Valentijn Overeem had what method?
Columns: ['Res.', 'Record', 'Opponent', 'Method', 'Event', 'Round', 'Location']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Loss', '7-5', 'Gary Goodridge', 'Decision (split)', 'PRIDE 21', '3', 'Saitama , Japan']
SQL:

assistant: SELECT "Method" FROM "Table" WHERE "Opponent" = 'Valentijn Overeem';