Briton Kelly Holmes deposed friend and training partner Maria Mutola as women's 800 metres Olympic champion on Monday in one of the biggest upsets of the Athens Games.

Holmes, who had never won a major title before and whose career has been blighted by serious injury, timed one minute 56.38 to win a blanket sprint to the line following a brilliant tactical display.

Mutola, the dominant force of the event for around a decade and who had helped to breathe new life into Holmes's career, went away empty-handed.

Silver went to Hasna Benhassi of Morocco with Jolanda Ceplak of Slovenia taking the bronze. Both were given the same time, 0.05 seconds behind an incredulous Holmes.

 "I can't believe it. I didn't realise I had won," the said the 34-year-old Holmes, who won bronze in Sydney. "I'm in shock -- absolute shock.

"I knew I was in front but had to see the replay twice to make sure. I was just digging in."

Holmes, who favours the 1,500m and will double up in Athens, had decided to run the 800 only just before the Games. "I might regret it if I don't run," she had said.

Mozambique's Mutola, who finished fourth, 0.08 seconds out of the medals, had hoped to become the first woman in Olympic history to win two 800 metres golds in succession.

She and Holmes are so close that many suspected the Mozambican had helped the British runner to win a world championships silver behind her last year by blocking other competitors.

Mutola looked stunned by the result. As Holmes held her hands to her face in disbelief before setting off on her victory lap, Mutola stormed out of the Olympic stadium without a word, smile or a wave.

She composed herself, however, to say: "Kelly and I train together, so she knows my weaknesses. She really deserves her gold."

Mutola, who has also won three world outdoor titles and six indoors, came to Athens with question marks over her form after a rare defeat which she had blamed on a hamstring injury.

Monday's reverse, however, was still a huge shock since most of her opponents, including Holmes and Ceplak, are in awe of both her talent and her brooding menace during races.

Mutola, who appeared to be trying to unsettle Ceplak before the start by standing close to her, started in lane five, with Ceplak and Holmes immediately inside.

At the break, all three were well back, with Ceplak fifth, Mutola immediately behind and Holmes, as so often, right at the back as American Jearl Miles Clark set the pace.

Mutola overtook the Slovenian at the bell, shadowed by Holmes, and the defending champion looked perfectly placed in third with 200 to go.

Her famed kick, however, failed to materialise. She got to the front but, clearly labouring, saw Holmes draw up to her shoulder.

Holmes, tying up in the final metres, just held on while Ceplak, who had looked out of it at 150 metres, stormed back to deny Mutola even the bronze.

The British runner had enjoyed the worst of luck before Monday's shock. She had only six weeks' training after injury before the 2000 Olympics and ran with a stress fracture in the 1996 Games. She was favourite for the 1997 worlds but ruptured her Achilles tendon and tore a calf muscle just before the competition.

It was Britain's second success in the event, the other coming in 1964 when Ann Packer won an equally unexpected gold.