The No.3-seeded Sharapova was hitting her serve and groundstrokes crisply throughout the match, but right at the end had to dig deep to cross the finish line - she missed her first four match points in a lengthy five-deuce game at 62 52. But she hit one last backhand winner on match point No.5.
"I thought I did a much better job today at being aggressive and playing a bit more consistently than in the previous match," Sharapova told reporters after the match. "The conditions today were a little bit easier as well. I'm really happy to be through to the quarterfinals of this tournament again."
Sharapova isn't just trying to win the Sony Open Tennis for the first time - she has been a runner-up four times, but never the champion - but she is also trying to become just the third player to win the Indian Wells-Miami double, after Steffi Graf, who did it twice, and Kim Clijsters, who did it once.
"I've been playing here since I first started playing professionally," Sharapova said. "I've visited this tournament as a fan myself and to come here every year, and to compete and be an athlete, is great."
And on the Indian Wells-Miami double? "It would be great to achieve that, but winning one on its own is special enough," the Indian Wells champion commented. "If I could win both that would be great."
Next for Sharapova is No.8 seed Sara Errani, who came back from a first set blowout to beat No.12 seed Ana Ivanovic earlier on. Ivanovic took the first set in just 23 minutes, but Errani took the momentum straight away afterwards, winning the first five games of the second set and eventually closing it out, 6-4; Ivanovic broke in the first game of the third but it was to no avail, as the rock solid defense and mix of depths and angles from Errani eventually wore the former No.1 down, 16 64 62.
"I'm obviously disappointed with the result," Ivanovic said. "I had a lot of chances today. In the second set I came back from 0-5 and had chances at 4-5; I had a few loose errors and she managed to win the set. The third set was close too - the score doesn't really show how close the set or match was.
"I really felt I've been playing some good tennis recently and in this tournament, so that's why it's disappointing to lose today. But I just have to look forward to the clay court season now."
And what exactly is Ivanovic's schedule coming up? "Next is Fed Cup, and then Stuttgart, Madrid and Rome," she said. "I'm looking forward to getting back to clay. It's one of my favorite surfaces."
Sharapova has beaten Errani in all three of their previous meetings, and in straight sets too - but in their last meeting it was a tight one, even saving two set points in an 82-minute opening set.
"Sara's probably one of the most consistent players on the tour, and she's getting really far in tournaments all the time," Sharapova said. "The last time we played was a tough one in Indian Wells - she played great tennis and it seems she's playing with a lot of confidence on hardcourts too.
"It'll be a tough one."