Fourth-seeded German Angelique Kerber had to dig deep in the second set on Monday to polish off a 6-1, 7-6 (7/4) third-round victory over Yanina Wickmayer at Indian Wells.
After easing through the opening set, Kerber trailed 4-1 in the second.
But the 25-year-old, ranked sixth in the world, was able to turn the tide after some encouraging words from her coach.
"He was coming to me and just reminding me of the game plan we had before the match and just telling me to focus on my game, play point by point and believe in my game," she said.
"It helps me."
Kerber had a breakthrough season in 2012, winning two titles and moving into the top 10 in the world rankings.
She has struggled to build on that success this year, in part because of a back injury that forced her out of Germany's Fed Cup team.
She lost her opening matches at her last two tournaments, at Doha and Dubai, but said her confidence is growing now that she has put together a couple of wins with no ill effects on her back.
"Now my confidence is of course back and I feel good, and I'm looking forward to playing tomorrow again," said Kerber, who will face Spanish qualifier Gabine Mugurza -- a 6-4, 6-0 winner over Magdalena Rybarikova.
Victoria Azarenka, the Australian Open champion seeking a title repeat in the California desert, was due on court later Monday against Belgian Kirsten Flipkens with a place in the last 16 at stake.
Former Indian Wells champion Caroline Wozniacki was also in action, taking on Russian Elena Vesnina, and former US Open champion Samantha Stosur of Australia faced China's Peng Shuai.