An out-of-sorts Serena Williams saw the defence of her Miami Open title come to an end as an uncharacteristic collapse saw her suffer a shock three-set defeat against Svetlana Kuznetsova on Monday.

Top seed Williams was searching for a fourth consecutive title and ninth overall in Miami, but she was defeated 6-7 (3-7) 6-1 6-2 by the inspired Russian.

Kuznetsova - who last beat Williams en route to winning the 2009 French Open - was crisp and accurate in her ball striking, while she was afforded plenty of cheap points by Williams' 50 unforced errors.

Williams appeared sapped of energy at times in the Miami heat and she was unable to muster a trademark comeback against the 2006 champion.

There was little sign of the struggles to come for the world number one early on as she raced into a 3-0 lead in the opening set, a stunning deft lob in game two bringing up a break point that was duly converted.

Kuznetsova roared back in game five with a stunning backhand pass that brought the match back to serve.

The breaker was a mismatch as Williams clinched the set with a stunning forehand winner, but the American was under pressure at the start of the second as Kuznetsova wasted three break points in game two.

It was a brief respite as a mixture of sloppy errors and accurate ball striking from Kuznetsova saw the Russian reel off five-straight games to level the match.

In no time it was eight consecutive games as Kuznetsova stole a 3-0 double-break lead in the decider, but Williams finally showed some fight to earn one of those back in game four and stop the rot.

However, the errors came back and a ninth double fault saw Kuznetsova regain the initiative and she held to love in the next game for a 5-1 lead.

Williams showed some fight to make Kuznetsova serve it out, but the world number 19 finished the job when her opponent sent a forehand long.