Former world number one Serena Williams wishes she was facing "literally anybody" other than her older sister Venus in the third round at Indian Wells.

Serena's WTA Tour comeback continued Saturday after the 23-time grand slam champion outlasted big-hitting Kiki Bertens 7-6 (7-5) 7-5.

The 36-year-old American star's victory set up an all-Williams affair in the next round, with the siblings set to meet for the first time since Serena beat Venus in the 2017 Australian Open final.

Looking ahead to the match, Serena Williams – unseeded for the tournament – told reporters: "She's had such a good year last year and playing fantastic tennis. But I have to play a seed regardless, sooner than later most times for the next couple of tournaments," Serena told reporters.

"So I have to be ready. Whether it's Venus or anyone else, it's going to be someone.

"Obviously I wish it was anybody else in the draw, literally anybody, but that's okay. Just have to go out there and see how I am and do my best."

She continued: "I really abhor every time we play, but I do enjoy the battle when I'm out there. It's just afterwards I don't like it as much."

Serena – a two-time champion at Indian Wells – was far from her free-flowing best against Bertens Saturday but she battled past the Dutchman after almost two hours on court.

Back in the main draw of a tournament for the first time since reigning supreme at Melbourne Park last year, having given birth to daughter Alexis Olympia in September, Serena managed to see off the spirited Bertens following 22 winners and 34 unforced errors.

"I'm getting there. I have a long way to go. I have such a long way to go," Williams said.

"It definitely felt better than the first round, but I'm still a little rusty. I'm still making errors that I don't normally make. I call this a trial run, of travelling with the baby and all of this is just so new to me."