Angelique Kerber won't let an imminent return to No 1, courtesy of Serena Williams's injury withdrawal, change her focus at the elite WTA hardcourt tournament in Indian Wells.

The German was on top of the world after two Grand Slam victories in 2016, but Williams returned to No 1 with her Australian Open triumph in January.

Kerber's best performance of the season so far was a semifinal run last month at Dubai, where she revealed she had been struggling with a knee injury.

So even with Williams sidelined and a return to the summit certain, Kerber said that she can't get distracted by the rankings but must focus on her aim of building momentum at Indian Wells and the tournament that follows in Miami.

"For me, it's more important to come here and win matches," said Kerber, the second seed whose latest rise to No 1 won't become official until after the tournament ends on March 19.

"Here in the US, this is what I am focusing on, playing matches and winning tournaments.

"Of course it's a nice feeling," she said of regaining the coveted top ranking. "But at the end, it's just a number before my name."

Despite a rocky start to the season, Kerber said she remains positive.

"I am practicing good and I have to make the transition from the practice to the match courts," she said. "In Dubai I was playing better."

Like all 32 seeds, Kerber enjoys a first-round bye, which means unseeded players were jockeying for position when women's play got under way in the combined WTA and ATP Masters tournament in the desert east of Los Angeles.

Puerto Rico's Olympic gold medalist Monica Puig dispatched American wild card Danielle Collins 6-0, 6-2 on Wednesday to set up a meeting with third-seeded Karolina Pliskova, who was inserted at the top of the draw when Williams withdrew on Tuesday.

Pliskova, runner-up to Kerber at the US Open last year, has already lifted titles in Brisbane and Doha this year, and even a second-round exit in Dubai hasn't shaken the confidence that took a giant leap with her run to the final at Flushing Meadows and a quarterfinal appearance at the Australian Open in January.

"Definitely I think the New York thing helped me a lot," she said. "I'm beating players I didn't beat before."

Pliskova, too, said her mind-set didn't change with Williams absent – although she acknowledged that it was a bonus not to face her in the early rounds.

"For me, it doesn't matter if she's playing or not," Pliskova said. "I was in her half, so obviously it's better not to play her in first rounds – but for me it doesn't matter."

WATSON V KONTA

In other first-round matches on Wednesday, Heather Watson out-lasted American wild card Nicole Gibbs 4-6, 6-2, 6-2 to set up an all-British clash with 11th-seeded Johanna Konta.

Sweden's Johanna Larsson beat Italian Camila Giorgi 7-6 (7/3), 6-3 to earn a shot at eighth-seeded Russian Svetlana Kuznetsova.

China's Wang Qiang beat Ukraine's Kateryna Bondarenko 4-7, 6-4, 6-4 to line up a meeting with Elina Svitolina, who has collected titles in Taiwan and Dubai this year.

The tournament is also without 2016 champion Victoria Azarenka, who completed the "Sunshine Double" of Indian Wells and Miami last year but is taking time off after the birth of her first child.

World No 4 Simona Halep is the fourth seed, hoping to kickstart a season hindered by knee trouble. Slovakia's Dominika Cibulkova, Poland's Agnieszka Radwanska, French Open champion Garbine Muguruza of Spain and Russian veteran Svetlana Kuznetsova round out the top eight.

Venus Williams, whose only showing since her scintillating runner-up finish to sister Serena at the Australian Open was a first-match exit at St Petersburg, is seeded 12th and could find herself taking on Kerber in the quarterfinals.