Maria Sharapova was shaky from the service line but the Russian world number two dodged danger at key moments to beat seventh seed Sara Errani 7-5 7-5 and reach the semi-finals of the Sony Open in Miami, Eurosport reports.Errani had four service breaks against Sharapova, who committed 14 double faults. But the 25-year-old Italian was even more vulnerable to the big-hitting Sharapova, who broke serve six times.Sharapova, bidding for a rare double following her win at Indian Wells earlier this month, will play 2008 runner-up Jelena Jankovic of Serbia in the semi-finals.The Russian is seeking a 29th career title in Florida. She has reached the final on four occasions in Miami, losing them all – to Kim Clijsters in 2005, Svetlana Kuznetsova in 2006, Victoria Azarenka in 2011 and Agnieszka Radwanska in 2012.“I’ve been so close to winning,” she said. “I would love to win this. I’ve been coming to this tournament since I was a little kid. It would mean a lot to win it.”The other semi-final features Serena Williams against Agnieszka Radwanska.In the men’s tournament, world number five David Ferrer overcame a sloppy start to defeat Austrian Juergen Melzer 4-6 6-3 6-0 and set up a Miami Masters semi-final against Tommy Haas.