Katherine Grainger successfully defended her title at the World Rowing Championships yesterday with a blistering performance in the women's quadruple sculls final, in which the British crew led from the first stroke to the last.

The men's lightweight four, stroked by anglo-Scot James Clarke, also won their final by carving their way through from fourth at halfway to hold off France and Italy in a perfectly-timed charge for the line.

The double success took Britain's medal tally at these Championships to 11, with the overall team title adding further lustre to the achievements. These included three bronzes in Olympic classes to go with the two golds - including both men's and women's eights yesterday; a gold, won by sculler Tom Aggar, and a silver in Paralympic classes; and a silver and bronze in the non-Olympic international events.

This was Grainger's fourth world title and her third successive win in quadruple sculls. The build-up to these finals had been troubled for Grainger and her Camelot-sponsored crew of Annie Vernon, Debbie Flood and Fran Houghton. They were stung by defeat to China in Amsterdam earlier this season and then Grainger suffered a recurrence of a severe disc injury that threatened her place in the boat.

Following intense medical treatment, she started the regatta racing at bow, but after the crew won their opening heat on Monday, she was gradually re-introduced to the crucial stroke seat, where she raced yesterday.

And Grainger's aggressive presence at stroke made all the difference. She blasted off the start to go a third of a length up after five strokes. "We knew we were the most powerful crew," the Scot said after, "but the risk is you lose the technical side of your rowing. We had so much passion in the boat but we knew we had to control it."

China followed the British quartet off the blocks but by halfway it was Germany, in front of a massive home crowd, who were challenging. The British crew came under pressure in the closing stages, but kept control to win by over a second with China in third.

"You hope that when you're under maximum pressure the technique comes naturally, and it did today."

This year's joy for Grainger and her crew was in sharp contract to last year's tears of disappointment, when they lost out to Russia, only to be upgraded weeks later when the Russians were found guilty of a doping offence.

"Yes, there were tears again this year, different tears though," Grainger added. "I was fine until I saw Steve Redgrave with tears in his eyes, though he probably won't admit that. I'm looking forward to waking up tomorrow knowing I'm still world champion."

Grainger now takes her godchildren to Eurodisney for a well-deserved short break before starting the build-up to trying to acquire the absentee from her medal collection, Olympic gold in Beijing.

The lightweight four's win came in one of the most competitive finals of the weekend, with less than four seconds covering all six crews on the line. The British crew sat in the pack for the first half of the race before stroke James Clarke unleashed a charge for victory. This was Britain's first win in this category since 1991.

In the lightweight pairs, Edinburgh's Danny Harte and his partner Matthew Beechey slipped off the pace early on, leaving themselves too much to do and they eventually finished fifth overall.