Former world number one Victoria Azarenka said she has room to improve in the coming weeks, despite winning on her return from a year out in Mallorca on Wednesday.

The Belarusian saved three match points to beat Japan's Risa Ozaki in her first match since taking time out of the sport after last year's French Open to give birth to her son.

"I don't think I gave myself enough opportunities to play better in the second set," Azarenka told the WTA Tour website.

"I started getting down on myself for making mistakes. That cost me the set and in the third, I felt unlucky at the beginning.

"There were a lot of ups and downs, good shots and then easy mistakes. That's something to expect after a long break, but definitely something I need to work on."

Azarenka, a two-time Australian Open champion in 2012 and 2013, was one game from defeat against Ozaki in her first-round tie when play was suspended due to bad light on Tuesday.

The 27-year-old rallied from 0-40 down as Ozaki served for the match to claw through 6-3, 4-6, 7-6 (9/7) in two hours and 44 minutes.

Azarenka will meet Croatian teenager Ana Konjuh in the last 16 in her only tournament ahead of Wimbledon, which gets underway on July 3.

"I definitely felt better on the tennis court, especially playing-wise," she added.

"I wouldn't say I had the best preparation coming to this tournament, but mentally, it's better to go through this kind of a match."

Azarenka, who gave birth to her first child, Leo, in December last year, no longer has an official world ranking and entered the grass-court tournament in Spain as a wildcard.

However she will play at Wimbledon using her protected ranking of sixth from 12 months ago.