CREATE TABLE table_203_551 (id DECIMAL, "goal" DECIMAL, "date" TEXT, "venue" TEXT, "opponent" TEXT, "score" TEXT, "result" TEXT, "competition" TEXT)

szalai scored only one more international goal against all other countries put together than he did against what one country ?
SELECT "opponent" FROM table_203_551 ORDER BY "score" DESC LIMIT 1
SELECT "opponent" FROM "table_203_551" ORDER BY "score" DESC NULLS LAST LIMIT 1