user: Question: When David McNamara was the opponent in the final, what was the tier?
Columns: ['Date', 'Tournament', 'Tier', 'Surface', 'Opponent in the final', 'Score']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['26 October 1998', 'Melbourne , Victoria , Australia', 'ITF', 'Clay', 'Toby Mitchell', '6–2, 6–4']
SQL:

assistant: SELECT "Tier" FROM "Table" WHERE "Opponent in the final" = 'David McNamara';