Cliff Lee helped the Philadelphia Phillies lead baseball with a 3.02 ERA. (Jeff Gross/GETTY IMAGES)

The extraordinary events of Wednesday night, when the Boston Red Sox and Atlanta Braves completed historic collapses with horrific losses on the final day of the season, left the 2011 postseason field as strong and healthy as any in recent memory. No one backed in. No one shut it down at the end.

In fact, the six division winners averaged nearly 97 wins apiece and won their divisions by an average of nearly 10 games. And the two wild-card winners, meanwhile, arrived after making heroic September charges. All eight teams posted winning records in September. The four first-round matchups — the Tampa Bay Rays at the Texas Rangers, the Detroit Tigers at the New York Yankees, the St. Louis Cardinals at the Philadelphia Phillies and the Arizona Diamondbacks at the Milwaukee Brewers — pit the merely hot against the scalding.

But even in this lofty company, one team stands out: the only team to cross the 100-win barrier, the only team that can be said to be in the midst of a mini-dynasty, the only team that can send an ace to the mound in pretty near every game in October.

And so, the question at the outset of the postseason is: Can anyone stop the Phillies?

And in answering that question, we offer a number: 3.5.

It is the new magic number for the Phillies, the number around which their postseason fortunes will pivot. And what is the significance of 3.5? It is the number of runs the Phillies must average — a modest, highly achievable number — to run the table in the postseason.

How do we know that? Well, we don’t, of course. But the evidence is clear. A year ago, the San Francisco Giants — a team that, like the 2011 Phillies, was built around starting pitching — won the World Series with an offense that averaged just 3.9 runs per game in the postseason. They did that, of course, with pitching — by allowing an average of only 2.7 runs per game.

If anything, the 2011 Phillies pitching staff is even better than that of the 2010 Giants, posting a season ERA (3.02) that is more than a third of a run lower and issuing a total of 174 fewer walks over the course of the season. So if anything, the Phillies need even less offense to win.

Here is another interesting thing about 3.5. If you gave the Phillies that many runs in every game this season (and yes, we understand that a team can’t score 3.5 runs in any single game), they would have gone 94-68. It’s a bargain the Phillies’ offense — which has sputtered at times this season — has come to appreciate: Give their pitchers more than three runs, and it’s generally a win.

Indeed, there are four reasons why the Phillies must be considered the overwhelming favorites to win the World Series: Roy Halladay, Cliff Lee, Cole Hamels and Roy Oswalt. Add a fifth reason: Ryan Madson, the right-handed reliever who has emerged as an elite closer in his first extended stint in the job. As the educated fan knows, the game changes significantly in October, and those changes only enhance the Phillies’ advantage.

In the postseason, teams may still carry 10 or 11 pitchers, but for the better teams the vast majority of innings are pitched by only a handful. For the 2010 Giants, 82 percent of their postseason innings were covered by four starters (Tim Lincecum, Matt Cain, Madison Bumgarner and Jonathan Sanchez) plus closer Brian Wilson. For the 2009 World Series-champion Yankees, 78 percent of their postseason innings were pitched by just three starters (CC Sabathia, Andy Pettitte and A.J. Burnett) and closer Mariano Rivera.

When the Phillies shocked the baseball world by signing Lee over the winter, to go along with Halladay, Hamels and Oswalt, it was not for the purpose of winning 102 regular season games — although such a thing could be expected. It was so that Lee could give them 40 or so lock-down innings in October, to go along with the 30-40 each from Halladay and Hamels, and the 20-30 from Oswalt. Halladay, Lee and Hamels ranked second, third and eighth in the majors in ERA this season.

There are good teams in this postseason that are scrambling to cobble together a rotation behind their ace (the Yankees, behind Sabathia), and teams that are facing tough questions about the status of would-be aces (the Rays, with struggling lefty David Price). And there are teams deep enough in pitching that they can start a 13- or 14-game winner in Game 4 (the Brewers, with Randy Wolf; the Rangers, with Colby Lewis).

But no one else can do what the Phillies can: send an ace to the mound anytime they want. A team can go a long way on four great starters, a dependable closer and 3.5 runs per game.

The World Series prediction here: Phillies over Tigers in five games.