Italian number one Francesca Schiavone was an early casualty in the Rome Masters after losing her opening round match to Ekaterina Makarova.
The out-of-form Schiavone, the 10th seed here and 2010 French Open champion, was beaten 6-3 6-4 by her Russian opponent as she slumped to a 10th defeat in her last 12 matches.
Number 12 Angelique Kerber of Germany was also made to battle hard before she progressed through to the second round with a 4-6 7-5 6-2 win Australian qualifier Anastasia Rodionova.
"It was very tough conditions because some of the court had shadows, some was sunny, and it was windy," Kerber said on www.wtatennis.com. "And Anastasia played very well - I was just thinking to fight and play point by point, and I'm very happy I won."
Serbian Ana Ivanovic, the 13th seed, had no such concerns though in her 6-4 6-3 win over Russia's Svetlana Kuznetsova in a battle between two other former Roland Garros winners.
Other players making it through their opening matches today were Anastasia Pavlyuchenkova, Julia Goerges, Anabel Medina Garrigues, Christina McHale, Chanelle Scheepers, Iveta Benesova, Shahar Peer, Vania King and Sofia Arvidsson.
In the men's event, Seeded trio John Isner, Gael Monfils and Nicolas Almagro all progressed through to the second round, although they did so in contrasting fashion.
Frenchman Monfils, the 13th seed, had few problems seeing off Russian Alex Bogomolov Jr 6-4 6-1 but 12th-seeded Spaniard Almagro needed a third set before beating Marin Cilic 6-2 3-6 6-0.
American Isner, the ninth seed, survived the biggest scare though as he was forced to go the distance by German Philipp Kohlschreiber before winning through 2-6 7-6 (7/3) 6-2.
Also, Bernard Tomic battled back from a set down to defeat Santiago Giraldo 4-6 6-2 6-4 and the Australian's reward is a second-round showdown with top seed and world number one Novak Djokovic, the defending champion here.
Argentina's Carlos Berlocq will face third seed and this weekend's Madrid Open winner Roger Federer in round two after defeating Blaz Kavcic 6-1 6-3 while his countryman David Nalbandian will take on fourth-seeded Andy Murray after knocking out Spanish qualifier Albert Ramos 6-3 6-4.
Also winning through the opening round were Fernando Verdasco, Italian wildcard Fabio Fognini, Stanislas Wawrinka and Radek Stepanek.