In terms of citywide impact, the Phillies' first World Series championship, on Oct. 21, 1980, had it beat. After a 97-year drought, an absolutely riveting postseason, and the Bob Boone-to-Pete Rose pop-up catch moments before, the explosion of joy and relief that followed Tug McGraw's Game 6-ending strikeout of Willie Wilson will be tough to match. It's kind of how Boston felt in 2004.
As far as any single athletic achievement in Philadelphia goes, Halladay's certainly ranks high. But until another NBA player scores 100 - or 90, or even 82 - nothing can top Wilt Chamberlain's 100-point night in 1962.
Still, there's something about Halladay's accomplishment that makes it feel weightier.
The difference, of course, is that unlike the ballyhoo surrounding the Phillies pitcher's no-hitter, Chamberlain's feat wasn't televised, wasn't covered by any big papers, and was witnessed by only 4,124 fans in tiny Hershey.
Since Halladay has done both in 2010, what's rarer, a perfect game or a postseason no-hitter?
Well, since only Halladay and Don Larsen have done it, the tendency is to say it's the latter. But it isn't. Not by a long shot.
There have been roughly 200,000 major-league games since 1876 and only 20 perfect games. Since two pitchers in each game have an opportunity, that means a perfecto happens only once every 20,000 chances.
Meanwhile, counting World Series since 1903, League Championship Series since 1969, and league division series since 1995, there have been 1,245 postseason games. With two pitchers in each, that's 2,490 chances. Two have done it. So the chances are 1-in-1,245.
So if Halladay's May 29 perfecto felt a little more special, it truly was.
Which of Halladay's pitching gems was the greater performance?
Given the circumstances, you'd have to go with Wednesday night's no-hitter.
