By Andrew Mooney, Boston.com Correspondent

In the death throes of the Bobby Valentine era, it was laughable to imagine the Red Sox as anything even close to resembling a feel-good story. Yet here we are at the end of April, with the Red Sox leading the AL East by three games while producing moments like this. And were those cheers from the Fenway faithful for John Lackey? It’s all too much to contemplate.

For a team not expected to do much of anything this year, Boston’s hot start comes as even more of a surprise. Let’s break down how they’re doing it, compared to their ho-hum start to the 2012 season.

The difference hasn’t come from the offense; in fact, the Sox have scored a nearly identical number of runs as they did last April. Daniel Nava and Shane Victorino have been pleasant offensive surprises, picking up the slack for the struggling bats of Will Middlebrooks and Stephen Drew. Still, on paper, this team shouldn’t produce nearly as much as last year’s lineup. One of the big question marks going forward is if the Sox will be able to sustain this level of run production—their team BAbip of .340 suggests a bit of a drop-off may be coming soon.

The transformation from a .500 team in April to a division leader has come about through improved performance on the mound. Resurgent stuff from Clay Buchholz and Jon Lester, as well as offseason pickup Ryan Dempster, has made Boston’s pitching staff into the American League’s second-best unit, behind only Texas. The bullpen has been on par with the starters; instead of comically blowing leads as they did last April, the relief staff, led by a healthy Andrew Bailey, has been dependable in locking up wins. As a whole, Boston hurlers have struck out nearly 100 more batters than they did through the first month of 2012, a big reason for their success.

Apparently that’s the formula for morphing from the city’s most scorned team into perhaps its most inspirational: a new cast of characters, solid bats, and lockdown pitching. Still, the team has yet to play even a sixth of its full schedule, so if you’ve been saving up some vitriol to spew at John Henry and crew, stay tuned.