Naomi Osaka may have lost three straight matches following her successful return from a maternity break, but the former world No. 1 said the only the direction left to go is up ahead of the Qatar Open.

The four-time Grand Slam champion, who gave birth to her daughter Shai in July, won her first match after 15 months away from the game at the Brisbane International last month before falling to Karolina Pliskova in the second round.

Osaka then suffered opening-round defeats at the Australian Open and Abu Dhabi Open against Caroline Garcia and Danielle Collins, but the 26-year-old said she had not lost her confidence.

"It definitely is hard for me to not be tough on myself, but after Abu Dhabi I actually have more confidence in myself, which is a little strange," Osaka told reporters.

"I feel like since I have seen the worst that can happen, everything else is a plus. In Australia I knew that I said I was only going to play in Dubai, so I feel like I have to take these tournaments as extra credit.

"Someone said to me it's like a very expensive practice, so I don't know, after they said that I felt pretty optimistic."

Osaka, who opens her Doha campaign against Garcia on Monday, said she preferred to face tough opponents like the Frenchwoman.

"I learn more from the matches," Osaka said. "So of course it's funny to hear I'm playing her again but I'm a little happy."

"She's always been a really nice person and I know I'm not supposed to think that about my opponent, but I know we also share the same birthday. At the end of the day, a Libra is going to win."