Alisa Kleybanova won her first match back after studded Sony Ericsson Open as a wild card Tuesday.
Kleybanova was in the world top 20 and rising before she was diagnosed with stage two Hodgkin's lymphoma last May.
The 22-year-old Russian underwent chemotherapy treatments in Italy before returning to the practice courts back in December and had to fight back to beat Sweden's Johanna Larsson on Tuesday.
Kleybanova dropped the first set, but rallied for a 2-6, 6-3, 6-2 victory and will face No. 22 seed Maria Kirilenko of Russia in the next round.
Earlier, former top-10 player Jelena Dokic came up a first-round loser on the hardcourts at the Tennis Center at Crandon Park.
Russian Ekaterina Makarova handled the former world No. 4 Dokic 6-1, 7-5 while breaking her serve six times in the 80-minute match.
Rising German Mona Barthel blitzed Hungarian Greta Arn 6-1, 6-0 in 55 minutes; while Bulgarian Tsvetana Pironkova drilled Croat Petra Martic 6-3, 6-2; and British wild card Heather Watson edged out Romanian Sorana Cirstea 6-3, 3-6, 7-6 (7-4).
Additional Day 1 wins came for New Zealand's Marina Erakovic, Zheng Jie and Zhang Shuai of China, Anna Tatishvili of Georgia and Lourdes Dominguez Lino of Spain.
Zhang is rewarded with a second-round match against Miami stalwart Serena Williams.
The top seed is also the defending Miami champion, Victoria Azarenka, who is fresh off her title at Indian Wells last week. The world No. 1 star and Australian Open titlist from Belarus is off to a 23-0 start this season.
Azarenka, who also titled in Miami in 2009, topped three-time Sony Ericsson Open runner-up Maria Sharapova in last week's finale at Indian Wells and last year's title tilt in Miami.
Azarenka is joined in a potent field by the likes of the Aussie Open and Wimbledon runner-up Sharapova, Wimbledon champ Petra Kvitova, former No. 1 Caroline Wozniacki, the Williams sisters -- Serena and Venus -- and two-time Miami winner and former No. 1 Kim Clijsters (2005, 2010).
The former top-ranked Serena is a five-time Miami champ (2002-04, 2007-08) and two-time runner-up, while the former No. 1 Venus owns three titles at the event (1998-99, 2001) and was a runner-up on another occasion.
The winner of the $4.828 million event will collect $712,000.