Veteran Tommy Haas backed up his upset of world No. 1 Novak Djokovic with a quarter-final victory over Gilles Simon on Wednesday to advance to a semi-final against David Ferrer at the Sony Open in Miami.
The 34-year-old Haas, who beat Djokovic on Tuesday, produced a strong encore performance in his 6-3 6-1 victory, when he produced an outstanding return game, breaking Simon once in the first set and three times in the second.
Haas will next face world No. 5 Ferrer who overcame a sloppy start to defeat Austrian Jurgen Melzer 4-6 6-3 6-0 in their quarter-final.
In the women's tournament Maria Sharapova was shaky from the service line but the Russian world No. 2 dodged danger at key moments to beat seventh seed Sara Errani 7-5 7-5 and reach the semi-finals.
Serving at 4-5 in the second set of a see-saw struggle, the third seed Sharapova saved three set points before winning the final three games to end the two hour, 29-minute battle.
"She had her chances to win that second set. Who knows what would have happened," said Sharapova, a four-time Miami finalist who has yet to win the tournament.
"I'm lucky to get to the next one and have a chance to be in the semis again ... the great thing is that I pulled through. I worked hard. I was steady, and I gave myself a chance to get here."
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 after she beat Italy's Roberta Vinci 6-4 6-7 6-3.
Third-seeded Ferrer, who has already won twice this year after notching seven tournament wins in 2012, raced through the final set losing just four points on serve and committing only four unforced errors to finish with a flourish.
The loss ended a nine-match winning streak for 42nd-ranked Melzer, who won earlier this month in Dallas.
The Spaniard will meet the winner of Wednesday's later match between Germany's 15th-seeded Tommy Haas, who knocked out world number one Novak Djokovic, and French 11th seed Gilles Simon.