ABU DHABI, United Arab Emirates (AFP) — Naomi Osaka said she was trying not to feel "like a failure" after her comeback hit another roadblock with a 7-5, 6-0 defeat to former world No. 7 Danielle Collins in the first round of the Abu Dhabi Open on Tuesday.

"I say some pretty harsh words about myself. I know the word, but if I say it, it sounds really bad. I felt a little like a 'failure,' but I don't want to be too harsh," Osaka told AFP in the UAE capital after her straight sets defeat.

The Japanese star returned last month from a 15-month absence from the tour, during which she gave birth to her first child Shai but has been handed some tricky draws and lost three of her four matches so far this campaign.

The former world No. 1 also lost in straight sets in the doubles later on Tuesday, alongside Ons Jabeur, but feels that performance helped her shake off her earlier disappointment.

"I'm less confident but I'm not too unconfident to think that I can't play really good tennis," four-time Grand Slam winner Osaka said.

"I really think I just need to get through a really tough match and then sort of acknowledge that that's going to happen quite a couple of times."

Despite a close opening set that witnessed supreme serving from both players, Osaka struggled in her service games in the second set and failed to convert any of her six break point opportunities to fall to the American qualifier in one hour and 23 minutes. 

"Everyone around me is telling me I'm playing well and I don't think I'm playing bad," she continued.

"I just need to believe in myself more and I think as soon as I got broken my belief dipped a lot."

Osaka will next head to Doha for the Qatar Open and said she "might have to play Dubai" but is unsure as of yet.

Meanwhile, Collins improved her head-to-head record against Osaka to 2-3 and will take on top-seeded Elena Rybakina in the second round.