MIAMI, FL, USA - The first round of the Sony Ericsson Open wrapped up on Thursday as the top half of the draw played their opening matches. The most notable winners were four of the world's Top 50, hailing from all around the globe and led by South America's No.1, Gisela Dulko.

Argentina's Dulko, ranked No.35 in the world, beat Spain's Lourdes Domínguez Lino handily, 62 64, setting up a second round clash with the No.3 seed, Jelena Jankovic. Other Top 50 players who won through to the second round were China's Li Na, who will next face No.29 seed Aleksandra Wozniak; Thailand's Tamarine Tanasugarn, whose next opponent is No.10 seed Agnieszka Radwanska; and Israel's Shahar Peer, who has the dubious honor of playing No.5 seed and three-time Miami champion Venus Williams next.

"Before this match I was nervous. I don't know why. Maybe because I didn't know how she played," Peer said about her 61 76(5) win over Tamaryn Hendler. "I had a good run last week in Indian Wells. She was playing well and stepped it up in the second set. I could have been there another hour if I didn't take the second set. So I'm happy but of course I will have to play better next round."

Peer has only played Williams once, falling to the American in the final of the indoor event in Memphis two years ago, 61 61.

"Venus is a great champion. I will just have to play better," Peer said. "I think if I play like last week, there is no reason why I can't make it a good match. Every day is a new day, so tomorrow I will play my doubles, work on some things then get ready for the next match. Hopefully I will do better than last time we played."

Other winners were María José Martínez Sánchez, Ekaterina Makarova, Sabine Lisicki, Anna-Lena Groenefeld, Tathiana Garbin, Barbora Zahlavova Strycova, Alla Kudryavtseva, Mara Santangelo, qualifiers Karolina Sprem, Julia Goerges and Michaella Krajicek, and last but not least, wildcard Alexa Glatch, who will face top seed and five-time Sony Ericsson Open champion Serena Williams next.

Players in the bottom half of the draw, which includes the likes of Top 8 seeds Dinara Safina, Elena Dementieva, Ana Ivanovic and Svetlana Kuznetsova, will play their second round matches on Friday, with the top half playing theirs on Saturday.