The A's like to think of themselves as "the Chihuahua that won't let go of your ankle." At least that's how GM Billy Beane modestly describes his small-market, small-budget powerhouse that just finished teaching the Red Sox and Yankees a lesson:

Beware of an opponent that has no money, but has no fear, either. The Little Green Engine took consecutive series from the East's best teams, and continue fueling an annual, dollar-less miracle.

	Miguel Tejada is second in the American League with 98 RBI.

Somehow, despite a $40 million payroll that ranks 29th in the big leagues, the A's are in everyone's faces: after taking 2-of-3 from both the Red Sox and Yankees last week, Oakland is just 4½ games behind the first-place Mariners in the AL West, and only 2½ games behind the Angels in the wild-card race.

Can the A's make it to the postseason for the third straight year? If momentum counts for anything, they've become a human tidal wave. Since May 24 the A's are 48-25, best in the American League and second in baseball only to the Braves.

"We're proud of our efficiency," Beane says. "Let's face it, we've had to re-invent ourselves because of the players we lost from last year. But I'd have to say we've recovered nicely."

The GM is talking about the combined absences of Jason Giambi, Johnny Damon and Jason Isringhausen -- three core players who helped the A's take the Yankees to the final game in postseason series in 2000 and 2001.

These aren't the same A's in 2002 -- obviously the offense isn't as explosive -- but in another sense, history is repeating itself. The A's still have the same, overpowering starting rotation that could potentially devastate any opponent in a short playoff series.

Don't think the Yankees are oblivious to the threat, specifically since they lost their series against the A's without facing Barry Zito. In fact, it was No. 4 starter Cory Lidle, who turned out to be Oakland's primary pitcher, outgunning David Wells in an 8-0 flogging on Saturday.

Mark Mulder pitched poorly on Sunday in an 8-5 loss to Mike Mussina -- sparing the Yankees the embarrassment of being swept at home -- but that was little consolation to the Yankees right-hander, who still hasn't found the elixir to a season-long slump.

"It's been for four and a half months now. This is the way it's going to have to be for this season," said Mussina, who allowed four runs and 11 hits in six innings. He's allowed 10 or more hits in three consecutive starts and is lugging around an ERA perilously close to 5.00 (4.95).

Mussina's decline has long-range ramifications to a possible A's-Yankees showdown in October. For the first time in five seasons, the Bombers may well forfeit their advantage in starting pitching, and will have to rely more heavily on Jason Giambi's and Alfonso Soriano's home-run power. That, and pray that Mariano Rivera stays healthy.

While the A's respect the Yankees' might, their pitching is what allows Beane to say, "If we can get to the postseason -- and that's the challenge this year, getting there -- then I like our chances against anyone, including the Yankees."

	“	We're proud of our efficiency. Let's face it, we've had to re-invent ourselves because of the players we lost from last year. But I'd have to say we've recovered nicely. ”
		— Billy Beane, A's GM

What's remarkable, of course, is that the A's are this dangerous despite a payroll that's less than a third of the Yankees'. But don't ask Beane if he feels sorry for himself, because he absolutely loves the quixotic challenge of puncturing the Bronx monolith.

But make no mistake: the A's wouldn't mind the comfort that turbo-dollars brings, either. Zito, for one, openly admires the Yankees' commitment to winning.

The left-hander said, "I'm sure there are owners out there who have more money than (George) Steinbrenner, but he's the only one with the guts to spend like that. And the Yankees don't just spend, they also make the right deals. They always seem to get the right player."

Zito was undoubtedly referring to Giambi, who was seduced by the Yankees' millions. But the A's have been re-invented, as Beane said. Just as Giambi carried the offense for the last two seasons, shortstop Miguel Tejada has become this year's top run producer.

In fact, Tejada, batting .301 with 27 home runs and 98 RBI, has suddenly become a bona fide MVP candidate -- or at least inching alongside Alex Rodriguez and Nomar Garciaparra in the debate over who's the game's best shortstop.

Derek Jeter used to be on the fringe of such conversations, but a recent 9-for-48 slump hijacked his average below .300 (.298, to be exact). The stronger, more explosive Tejada wisely avoids discussing whether he's eclipsed Jeter, however, saying, "He's a playoff guy. He's a superstar. That's who I want to be."

Indeed, it's the postseason that's separated Jeter from other great players, and the Yankees are hoping their October pedigree will cover up all the little blemishes that are now visible.

But the A's promise they're not intimidated. With a 23-9 record in one-run games, they're obviously tough. And winning 4-of-6 in what Beane called, "our biggest road trip of the year so far," the A's are proving once again, there's more to winning than cash-flow.

Listen to the sound of the Little Green Engine: no money, no fear.

Bob Klapisch of The Record (Bergen County, N.J.) covers baseball for ESPN.com.