Fish knocks out champion Murray in Miami

Unseeded American Mardy Fish recorded a shock 6-4, 6-4 win over world number three and defending champion Andy Murray in front of a packed crowd in the Sony Ericsson Open second round on Saturday.

Top seed Roger Federer then avoided Murray's fate with a 6-3, 6-3 victory in just over an hour over Ecuador's Nicolas Lapentti in the late match.

Florida resident Fish took control by seizing the opening set against the Briton and the writing was on the wall for Murray when he surrendered his serve in the first game of the second.

"I just wasn't very good today and I'm going to need to get a lot better," Murray told reporters.

"Mardy served well when he needed to especially in the second set," added the Scot who will be replaced at number three in the next rankings by Spain's Rafa Nadal.

"You can kind of get away with playing badly. I don't really mind that but mentally the last few weeks I've been really poor and it's unacceptable."

Murray was again outplayed and hit two aces against his opponent's eight.

Fish sported a wide grin as he celebrated his victory by pumping both fists close to his chest. He then signed the courtside television camera 'Hi dad'.

"My dad wasn't able to be there today but my mum was," said the American. "It's really nice to have them come down.

"They don't get to watch much," said Fish, who last beat a top-five opponent when he knocked out Federer at Indian Wells in 2008.

Fifth-seeded Swede Robin Soderling went through with a 7-6, 6-0 win over Australian Peter Luczak.

In the women's event, third seed Venus Williams defeated Italy's Roberta Vinci 6-1, 6-4 in a third-round match.