TORONTO, Canada -- Naomi Osaka eased into the third round of the Rogers Cup on Wednesday, as the World No.2 claimed the first set over Tatjana Maria before the German qualifier retired from the match due to a left abdominal injury.

Osaka had not played a match since losing to recent nemesis Yulia Putintseva in the first round of Wimbledon, but the Japanese star earned her first match-win since mid-June by cruising through the first set before her opponent retired prior to the start of the second set.

"I thought I played really well despite the fact that we only played one set," Osaka said in her post-match press conference. "I think that I was able to do what I wanted, which was go for the shots that I had the opportunity to. And, of course, there were, like, a couple unforced errors, but I think that's part of the process."

"For me, I'm just happy that it was my first match in a while and I was able to get in the groove of things quickly," the former World No.1 continued.

The encounter took 33 minutes in total and puts Osaka in pole position to reclaim the World No.1 ranking at the end of the week. By virtue of this match alone, Ashleigh Barty will be displaced from the top spot, and only a deep run by Karolina Pliskova could prevent Osaka from returning to the summit.

Read more: No.1 Scenarios: Barty loss opens door for Osaka, Pliskova in Toronto

Before Maria's retirement, No.2 seed Osaka was exhibiting fine form as she returned to hardcourt, the surface on which she has won the last two Grand Slams. Osaka had 17 winners in the match, to 15 unforced errors, and allowed Maria to hit just a single winner in their sole set.

Osaka will face either 18-year-old qualifier Iga Swiatek or former World No.1 Caroline Wozniacki in the round of 16. "I've played and practiced with Caroline a couple times," said Osaka. "I have never won, so I know that's going to be very difficult. She's one of the best returners in the game. She moves really well, and she's quite a good counter-puncher too. Like, I know what I have to expect going into that."

"I have never played [Swiatek] before," Osaka continued. "I have seen a couple of points of her playing, like, around at different tournaments, but I've never really sat down and watched. So I think I'm going to have to do that tonight. But she's young, and young people usually have no fear. I know that from experience."

Osaka’s return game was fierce from the outset, as she held three break points in the opening game, then finally went up a break at 2-1 on her fourth break point of a six-deuce game. Osaka continued to ramp up her returning prowess, quickly racing to 0-40 in Maria’s next service game before the German double faulted to drop serve at love and cede a 4-1 lead to the No. 2 seed.

Osaka zipped to double set point at 5-2 with a backhand winner up the line, and converted her first opportunity with a cracking crosscourt forehand winner, collecting the one-set lead after just over one half-hour of play.

Maria called for the trainer after the opening frame was completed, and after a brief consultation, the German quickly realized she would be unable to continue because of her abdominal injury, and walked over to shake hands with Osaka.