CREATE TABLE "singles_wins" (
  "date" text,
  "tournament" text,
  "tier" text,
  "surface" text,
  "opponent_in_the_final" text,
  "score" text
);

Question: When David McNamara was the opponent in the final, what was the tier?
SQL: SELECT "tier" FROM "singles_wins" WHERE "opponent_in_the_final"='david mcnamara';