The top two seeds in the women's singles experienced mixed fortunes at the Indian Wells event earlier today, with Serena Williams surviving a scare against fellow American Sloane Stephens, but Maria Sharapova going out at the hands of the reigning champion Flavia Pennetta.

Williams is back at the event for the first time in 14 years, but had said that she was feeling more comfortable at the BNP Paribas Open after her deliberate boycott, in the aftermath of her demolition of Zarina Diyas in the previous round. The 33-year-old struggled in the early stages against her 21-year-old opponent Stephens, making a clutch of errors and serving poorly, so much so that she lost the first set on the tie-break.

After that Serena showed more of her normal standard of play in sets two and three to take the match 6-7 6-2 6-2. She will now face Switzerland's Timea Bacsinszky in the last-eight. Serena will need to reduce the errors in her game one expects if she is to repeat her title success of 2001, given that she surrendered a massive 52 unforced errors and 9 double faults, although she did of course still find a way to win.  

The Italian number 15 seed, Pennetta came through 3-6 6-3 6-2 in a see-saw tussle with Sharapova, but it was the errant play of the Russian that ultimately cost her the match, as 42 unforced errors and 11 double faults only too clearly demonstrated. Pennetta was by no means perfect herself in terms of wastefulness, with 34 unforced errors of her own.

There was also a rather odd moment during the first set when Pennetta left the court, apparently because she became "emotional" and needed to release the tension by letting "everything out" and screaming. The break seemed to do her good by the end of the match, as she rattled off the last seven games.  

There was a further shock when Lesia Tsurenko of Ukraine, who was a qualifier in California, put out last year's Wimbledon finalist and number 6 seed Eugenie Bouchard of Canada in three close sets, 6-7 7-5 6-4.

Bouchard explained her disappointing performance on feeling "sluggish" from the start of the match.

The number three seed, Simona Halep of Romania had no such difficulties in defeating the Czech Karolina Pliskova 6-4 6-4.