Yet they have managed to fly below the radar, for the most part. And that's just fine with them.
"Maybe the fact that they don't know us helps," said veteran utility man Willie Bloomquist.
"It's all right; it's not a bad spot to be in," second baseman Kelly Johnson said.
Following back-to-back last-place finishes, the D-backs played poorly during Spring Training and were the trendy pick to finish at or near the bottom of their division.
Their play during the first six weeks of the season did not do anything to change people's opinions, but starting with a 1-0 win over the Dodgers on May 13, the D-backs have gone 49-32 and, following Thursday's dramatic come-from-behind win, lead the defending World Series champions by a game in the NL West.
"First and foremost, it's why you don't pay attention to what people say about you," Bloomquist said of the preseason predictions.
Bloomquist is a perfect representative of the new attitude of the D-backs. He's a grinder, a player who has survived for 10 years in the big leagues by playing with a chip on his shoulder and running out every grounder as though his life depended on it.
After taking over as general manager in late September, Kevin Towers surveyed the clubhouse and didn't like what he saw. One of his first priorities was to change the mindset by bringing in veteran free agents like Bloomquist, catcher Henry Blanco and infielder Geoff Blum, while also dealing for closer J.J. Putz.
"Unfortunately, when you lose a lot, you kind of accept it," Bloomquist said. "It takes kind of an attitude to change that culture to where we're not going to accept losing anymore. It takes some time to develop that, but when you do, it just becomes the norm. It just becomes a habit, just like losing does. Hopefully, that's the direction we're headed."
Towers also decided to stick with interim manager Kirk Gibson, whose competitiveness is legendary, and the two of them assembled a coaching staff that would garner respect in the clubhouse and share their extreme distaste of losing.
"I think that trickles down to players," right-hander Ian Kennedy said. "And then you get players like Willie who are just grinders their whole career, and he really hates to lose."
The strength of the D-backs is clearly their hitting, as they rank third in the NL in runs scored and lead the circuit in homers.
A huge part of their offense has been 23-year-old right fielder Justin Upton, who has started to become the five-tool player many envisioned when he was taken with the No. 1 overall selection in the 2005 First-Year Player Draft.
Befitting a team that lacks big names, the club has relied on contributions up and down the lineup.
Center fielder Chris Young had a hot streak before the All-Star break, Bloomquist provided a spark in April when shortstop Stephen Drew missed the season's first six games and has filled in admirably at short since Drew went down with a season-ending right ankle injury in mid-July.
Johnson, who was non-tendered by the Braves after the 2009 season and was quickly scooped up by the D-backs, is having a down year in terms of batting average but is still providing power and driving in runs.
There has been good fortune involved as well. Third baseman Ryan Roberts came to Spring Training in the best shape of his career after admittedly getting too comfortable following a breakout season of sorts in 2009, when he was 28. He led the Majors in hitting during March, but he would not have made the Opening Day roster had Blum not injured his knee.
While his average has tailed off, Roberts has come up big in crucial situations and is hitting above .300 with runners in scoring position. Among NL third basemen, only the Cubs' Aramis Ramirez has a higher OPS (on-base plus slugging) than Roberts' .810 mark.
Miguel Montero has provided above-average production for a catcher, and left fielder Gerardo Parra has contributed with his bat, but even more so with his defense.
"I think that we're well aware about how we're going to win our games and how we're going to win this division," Johnson said. "It's not going to be a breeze. Each game is going to be pretty tight, and there are going to be guys on base for us to tie it up; there are going to be guys on base for the other team. The majority of the time, we've been playing really good in those type of games, and that's a good quality to have heading down to the wire."
Pitching-wise, the D-backs have relied on Kennedy, 26, and Daniel Hudson, 24, who have formed a dominant one-two punch at the top of the rotation.
The friends, who locker next to each other at home, have been paired back-to-back in the rotation for most of the season, with Hudson following Kennedy, which has led to a healthy can-you-top-this type of competition.
When Kennedy, who at 14-3 has the best winning percentage in baseball at .824, had a rare poor outing prior to the All-Star break, Hudson followed with one of his own the next day.
"He came up to me before my next start," Kennedy said of Hudson, "and said, 'I'm going to need you to throw a shutout next time out because apparently I do the same thing you do.'"
"I'm just rooting for him to win the Cy Young, because that would mean I had a good season, too," joked Hudson, who has 11 wins of his own.
Veteran Joe Saunders has been good in the No. 3 spot, and Josh Collmenter gave the team a boost by pitching outstanding in his first six starts after being promoted from the Minors. Micah Owings and Barry Enright were used to fill out the rotation before Towers landed Jason Marquis from Washington just before the July 31 non-waiver Trade Deadline to fill out the rest of the rotation.
The bullpen, which had the third-worst ERA in Major League history last year, has been much improved thanks to the signing of Putz, who is 27-for-31 in save opportunities, and Towers' acquisition of setup man David Hernandez, who was 9-for-9 in converting saves during Putz's absence due to elbow tendinitis.
Putz has not only given the team its first legitimate closer since Jose Valverde in 2007, but he has also provided leadership among the relievers, who at his urging do their own pregame stretch on the field before the rest of the team.
"I think the key to the bullpen this year is J.J.," Montero said. "I think he's helped the bullpen big-time. That's what we were missing -- a veteran guy to be a leader there."
Despite their play thus far, there is plenty of skepticism about the D-backs' ability to stick with the Giants down the stretch.
"We're probably under the radar just because the guys that pick those things didn't pick us, so they're still waiting for us to drop off," Johnson said. "But our pitching has been really good for four-plus months, and there's no reason it won't continue. We'll be in the majority of our games right up until the end."
Gibson has molded this team into the image he wants -- a collection of guys who play hard night in and night out.
For Gibson, a former two-time World Series champion, winning can be just as much of a problem as losing if it breeds complacency, so even after a 6-3 California road trip earlier this month during which his club took two of three from the Giants, Gibson was leery.
"From where we are today, we have so far to go," Gibson said. "You just need to remain so humble and keep things in perspective to a huge degree, and that's what we'll do."