Williams, playing her third match at Indian Wells after deciding to end a 14-year boycott of the event where she had suffered alleged racist abuse, enjoyed plenty of support but struggled early to find her form.

Stephens, who reached the quarter-finals a year ago, looked ready to return to the last eight after breaking Williams twice to open the match but in the end there was no denying Williams as she extended her winning run to 14 matches.

"I don't feel like I need to come here and win the trophy," Williams told reporters. "I feel like this is more than I have ever imagined doing. I never imagined even having an opportunity to come back.

"I feel like I have been a champ here, and I'm really happy with every match that I win and every result. For me it's all icing on the court."

On another sun-bathed afternoon Stephens got the contest off to a bright start charging in front 3-0.

But Williams, who has not lost since last year's WTA Finals in Singapore, quickly got her game in gear sweeping through the next four games before her opponent could again hold serve.

Displaying plenty of grit of her own, Stephens dug in to force the opening set to a tiebreak that she dominated.

Playing with a greater urgency, Williams broke Stephens to open the second and would break her compatriot again to go up 5-2 before serving out the set to level the match.

The third set followed a similar script as Williams, playing her first event since winning her 19th grand slam title, and sixth at the Australian Open, recorded the early break to secure a 2-0 advantage. She broke again in the seventh game and held serve to close out a challenging test in two hours, six minutes.

"I thought I played a really solid first set," said Stephens. "Obviously I was playing the number one player in the world so it was going to be a little tough."

In other matches, third seeded Romanian Simona Halep rolled past 14th seeded Czech Karolina Pliskova while 12th seeded Spaniard Carla Suarez Navarro be Briton Heather Watson.

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