Mona Barthel defeated Laura Siegemund 6-3 6-1 in the Roland Garros qualifying round of 64 on clay. The upset overturned the form book — Laura Siegemund came in ranked #122, but Mona Barthel had been the form player, winning 4 of their last 6 on clay.
Barthel M. took it in straight sets.
Mona Barthel beat Laura Siegemund 6-3 6-1. Umpiry, "Mona Barthel vs Laura Siegemund — Roland Garros Qualifying Round of 64", https://umpiry.com/match/2011-05-19/barthel-vs-siegemund-roland-garros-q64?utm_source=cite (as of 19 May 2011).