MonaRR

The scoreboard screen behind the baseline displayed billboard-sized images of the players on Stuttgart's center court, illustrating the competitive quandary Marion Bartoli confronted.  The world No. 7 spent the day feeling Mona Barthel's presence over her shoulder and looking overwhelmed facing the powerful German, who played larger-than-life tennis.

The 21-year-old Barthel blasted Bartoli off the red clay in a thorough, 6-3, 6-1 thrashing that spanned 71 minutes. It was Barthel's first career victory over a Top 10 player, and if she can consistently produce the commanding tennis she delivered today, she may be headed for the Top 10.

A year ago, Barthel was an explosive, erratic world No. 196 who failed in three attempts to qualify for Stuttgart. This week, she's swept former French Open champion Ana Ivanovic and 2011 French Open semifinalist Bartoli in succession to reach her fourth quarterfinal of the year.

Bartoli is at her best hugging the baseline, taking the ball on the rise, and firing her trademark two-handed strokes into the corners, but Barthel came out dictating play from the first ball. The depth of the German's drives backed Bartoli up and sometimes forced her to take one hand off her racquet—she hits with two hands on both sides—to swat one-handed running retrievals.

Barthel's bold serve is becoming one of the biggest weapons in women's tennis. She slammed 11 aces against Ivanovic and hit seven today, winning 22 of 26 points played on her first serve. The 35th-ranked Barthel effectively muted one of tennis' most lethal returners in surrendering just eight points in 10 service games, drilling wide serves that sometimes left Bartoli waving in vain at the blurring ball.

It's an odd sight to see the offensive-minded Bartoli forced to defend, and it was an unsettling experience for the Frenchwoman, who double faulted to hand Barthel the break and a 3-1 lead. That was all the slender power merchant needed, as Barthel dropped just three points in her final three service games of the set, pounding a body serve to close the 36-minute opener.

That hold sparked a five-game run, as Barthel surged out to a 4-0 second-set lead before Bartoli finally got on the board. It was a short reprieve as Barthel, whose two-handed backhand is one of her biggest weapons, hit consecutive backhand winners followed by a clean forehand winner up the line to hold for 5-1. The beauty of Barthel's game is she's much more than a basher of the ball; she has variety, which she showed on match point, sending Bartoli scurrying side-to-side before curling a short-angled, cross-court backhand winner with sidespin to seal an impressive victory.

This young German generation is filled with success stories: Andrea Petkovic cracked the Top 10 last year, Julia Goerges is the reigning Stuttgart champion, Sabine Lisicki reached the 2011 Wimbledon semifinals, and 2011 U.S. Open semifinalist Angelique Kerber has won two titles this year. But Barthel may be most talented of them all. She could face No. 1 Victoria Azarenka next; three of Barthel's eight losses this year have come to Vika, including a 7-6-in-the-third defeat at Indian Wells.