SAN FRANCISCO – Alex Smith is 34. And that's ancient in NFL years. On Sunday he had the finest game of his career. In doing so, he reminded us of what a great quarterback he still is.In no way was this a surprise. His numbers over the past four weeks are startling. He's averaged 306 yards, six touchdowns and 0.8 interceptions a game. His quarterback rating is a ludicrous 143.2. It would be the fourth best quarterback rating of his