Did anyone outside Melanie Oudin’s family members, close friends, and coaches know about a 17-year-old from the Atlanta suburb of Marietta, Georgia, before the 2009 Wimbledon Championships began?

Didn’t think so.

But now, this uncommonly resourceful teenager is on the minds of every pundit, scribe and broadcaster at the All England Lawn Tennis and Croquet Club. Oudin became the headline story of week one at SW19 by shocking sixth-seeded Jelena Jankovic in Saturday’s third round. The 6-7 (8), 7-5, 6-2 triumph on Court 3 sends the Wimbledon newbie into Monday’s fourth round with the assurance of a paycheck no smaller than 53,000 pounds. Oudin’s accomplishment is remarkable enough in its own right, but the road that led the 17-year-old to the Saturday spotlight makes her feat that much more phenomenal.

Oudin had never won a Grand Slam match when she boarded a flight to London a little more than a week ago. Relegated to the qualifying rounds, those unforgiving yet off-the-radar proving grounds in professional tennis, Oudin managed to crank out three match wins and crack the main-draw field of 128. Merely busting into the bracket at a major tournament is an achievement that eludes thousands of tennis lifers who toil on the challenger and futures circuits for meager prize money that often fails to cover travel and medical expenses. Oudin–already a participant in two other slam tournaments–managed to hit the big-time in her sport’s most famous setting… and that was before she took the court for her first-round match on Tuesday against a pretty formidable foe, 29th-seeded Austrian Sybille Bammer.

Improbably yet undeniably, Oudin–filled with confidence as a result of her wins in the quallies–remained unflappable against opponents with far more credentials. Bammer reached the quarterfinals of the 2008 U.S. Open, and won the first set against her American counterpart. Oudin, however, didn’t flinch at all, taking the next two sets while dropping just six games. The result established a pattern that would remain in place for the rest of this magical week.

In the second round against Kazakhstan’s Yaroslava Shvedova, Oudin dropped the first set but again rallied to take the final two sets. How many games did the 17-year-old lose in the final stanzas? Yeah–six. Players this young, and this unaccustomed to the magnitude of major-tournament tennis, will typically waver when they get punched in the mouth by more experienced opposition, but Melanie Oudin has oozed with self-belief no matter what the score or circumstance. Against Jankovic, the former world No. 1, this quality emerged to a superabundant extent.

Oudin had four set points in the first set against the 24-year-old Jankovic, a one-time slam finalist and a five-time participant in the semifinals of a major. Yet, on each of those four points, the American novice coughed up an unforced error, which allowed the No. 6 seed to get out of jail and win the set in an extended tiebreak. While Jankovic needed a 12-minute medical timeout (for dizziness and heat exhaustion) after the set ended, the fact still remained that Oudin had to win two sets against an accomplished adversary. Jankovic is a far cry from the player who had contended for Grand Slam championships in recent years, but the Serbian star is familiar with the rigors of the WTA Tour. Oudin might have had a physically frail opponent on her hands, but the knowledge of her missed opportunities in set one had to weigh on the American’s mind. As the second set remained on serve after nine games, Oudin encountered the moment when her mental toughness would be tested as never before.

With Jankovic serving first in the set, Oudin had to toe the service line, on serve, at 4-5. At 30-all, Oudin–though not trailing by a break–still found herself two points away from ultimate defeat. Jankovic, for all her inadequacies in this match and, on a larger level, throughout a disappointing 2009 season, was just a heartbeat away from escaping this match, gaining a precious day of rest on Sunday, and remaining a factor heading into the second week of Wimbledon. The feel-good ride of Melanie Oudin was just about to end if the teenager couldn’t call forth a new level of composure.

Sure enough, the 17-year-old played the following cluster of points with the poise of someone 10 years older. Employing a variety of shots that are foreign to a generation of baseline-hugging ball-bashers, Oudin–with a trusty drop shot at her disposal–held for 5-all and then broke for a 6-5 lead. Given the chance to serve out the set, a pleasing yet paralyzing prospect for any tennis player in a match of such magnitude, Oudin’s nerves held steady once again. The American took care of business and sent the match to a third and deciding set. With Jankovic’s foot receiving attention after the set ended, the struggling Serb–already beset by whole-body weakness–had little left in the tank. Oudin’s ability to overcome first-set stumbles in previous matches helped her out on Saturday; the 17-year-old with the furious finishing kick produced yet another 6-2 set in a decider, her second of The Championships. While Jankovic is left to ponder a disastrous 2009, Melanie Oudin carries on, into the second week of Wimbledon for a date with 11th-seeded Agnieszka Radwanska on Monday.

And so it is: A player without a Grand Slam win heading into this tournament; a player with a world ranking of 124; a player who didn’t receive one of the many wild cards handed out to British teenagers, and who had to play her way through the quallies as a result, has now found herself in the round of 16 at Wimbledon.

Pretty heady stuff for a 17-year-old, right? Just don’t expect Melanie Oudin to lose her sense of perspective. With the focus and concentration she’s displayed in one otherworldly week of tennis, the “Marvel from Marietta” can make fourth-round appearances at slams a rather regular occurrence.