(CNN) -- She might have been out of the game for over six months but Venus Williams was back in the groove immediately in Miami, losing just three games in a victory over Kimiko Date-Krumm.
Williams has been sidelined since the U.S. Open in August last year after being diagnosed with Sjogren's syndrome -- an incurable condition which affects energy levels and causes pain in the joints.
The seven-time grand slam winner took just 77 minutes to beat her Japanese opponent and set up a third round meeting with Czech No. 3 seed Petra Kvitova,
It marks a big breakthrough for the former World No. 1, who insists she never thought about quitting the game she loves.
In an interview with CNN, she said: "When you don't feel well and things are taken away from you, it's hard to stay positive. But, for me, it is not an option to get negative or to feel sorry for myself.
"It's easy to say, 'I've done enough' -- or it would be easy to go on a permanent vacation. But I need to look back and know that I gave everything.
"I know I still have so much more. Before I was sick I was on top of the world in singles and doubles. So that's my goal, to return to that."
Williams is playing in Miami as a wild card and has won the event three times previously.
Another former world No. 1 also made a successful comeback in Miami, as Kim Clijsters overcame her rustiness to beat Jarmila Gajdosova, from the Czech Republic, in three sets.
The Belgian has been sidelined for nearly two months with an ankle injury, her last appearance coming at the Australian Open in January where she lost in the semifinals to Victoria Azarenka, the eventual champion.
Due to a string of injury complaints that affected her shoulder, abdomen and wrist as well as her ankle, this is just Clijsters sixth appearance since the tournament in Miami last year.
"It's always tough to get that first match rhythm under your belt," Clijsters told the WTA Tour's official website. "When it comes down to my game I felt I wasn't quite going through my shots as I should have.
"I was just trying to find that rhythm, but on the other hand maybe forgetting to still play aggressive tennis.
"But as I started to feel more comfortable with the conditions and being in a match situation again I was hitting better, and that definitely showed in the second and third sets."
Clijsters, who has dropped to 37 in the world rankings due to her absence, will now face No.14 seed Julia Goerges next.