Matt Cain is a really good pitcher. Twice in his career before 2012 -- on May 21, 2006 and again on May 28, 2010, Cain allowed just one hit in a complete-game shutout.

It isn't May yet, but Friday afternoon in San Francisco, he approached baseball immortality.

He retired the first 17 batters he faced in the Giants' home opener against the Pirates. Up stepped James McDonald, the Pirates' starting pitcher, who before Friday afternoon had six hits in 87 career at-bats.

You know what's coming next, of course -- McDonald ran the count to 2-1 and on Cain's fourth pitch, a 91-mile-per-hour fastball that got up in the zone, he hit a sharp ground ball for a single in between San Francisco shortstop Brandon Crawford and third baseman Pablo Sandoval:

That was the only hit, and the only baserunner, Cain allowed in a 5-0 complete-game shutout over the Pirates. In finishing his third career one-hitter, Cain threw 110 pitches (73 strikes) and struck out 11. It's the highest game score for any pitcher in the major leagues this season so far -- 97 -- and only 11 other games by pitchers have had a higher game score since 2000.

So that's impressive. This is also impressive:

In MLB history, 6 guys would've had a perfect game except they allowed the opposing pitcher to reach base once. Last: Jimmy Jones, 1986 — Trent McCotter (@trentmccotter) April 13, 2012

The Jimmy Jones game referred to was Jones' major-league debut, on September 21, 1986; the opposing pitcher, Bob Knepper, had the only hit -- a third-inning triple.

Matt Cain's third career one-hitter, thus, was not only unusual, but the best start of his career. One day, he'll likely throw a no-hitter, or even a perfect game. But he'll probably be happy if he doesn't have to face James McDonald again any time soon.