KEY BISCAYNE, Fla. -- Maria Sharapova's quest for her first title at Key Biscayne continues.
Sharapova, who moved into a semifinal matchup with Serena Williams, rallied from being down a break in the first set to oust Petra Kvitova 7-5, 6-1 on Tuesday and earn a spot in the semifinals of the Sony Open at Key Biscayne, where she's been a finalist five times but has never won.
The fourth-seeded Sharapova -- who needed three-setters to get through her two most recent matches at Key Biscayne -- feasted off 30 unforced errors made by the eighth-seeded Kvitova, who lost 11 of the final 13 games.
"I love the energy here," Sharapova said.
Williams, the defending champion, won 62 of 100 points in her 6-2, 6-2 romp over fifth-seeded Angelique Kerber.
Williams broke Kerber twice in each set, faced only one break point and held a more than 2-to-1 advantage in winners.
"It's really special," said Williams, who makes her home in South Florida and has been wearing outfits with Miami Dolphins colors in this tournament. "I live so close to here. I can drive here ... it's a great opportunity to play at home."
An unattended backpack left near the main gate impacted spectators' exit as they were trying to leave the facility after Williams' win.
Police stopped vehicle and foot traffic in the immediate area because the bag. Authorities then found it did not present any safety risk.
Det. Roy Rutland of the Miami-Dade Police Department said personnel working at the tournament found the bag. Rutland says the department's bomb squad was responding "to mitigate the potential threat."
Hundreds of people were stopped at the gate.
"There was a bomb threat and a lockdown but that's all I know about it," Williams said shortly after the situation ended. "Scary."
The start of play was delayed nearly an hour by rain, and Sharapova's match was briefly halted by a drizzle.
Also Tuesday, former world No. 1 Martina Hingis teamed with Sabine Lisicki to reach the women's doubles quarterfinals.