Scalps do not come much more highly prized than that of Ben Ainslie, four times Olympic medallist, including a hat trick of golds, and skipper of the Team Origin America's Cup challenge.
But his was just one of four, including former world champion Peter Gilmour of Australia, that Ian Williams, himself a double world champion, managed to knock off before lunch on the opening day the Stena Match Cup, the fifth of 10 in the World Match Racing Tour.
The familiar bogey of a sail handling error, though, this time, perhaps compounded by some gear malfunction, cost Ainslie his well-won lead. Williams swept by as free-flapping spinnaker wrapped itself around the bow and caused problems Ainslie's Team Origin crew all the way up the second windward leg.
Ainslie had been 10 seconds ahead the first time round; he was 22 seconds behind the second time and even his legendary downwind helming skills could not close that gap.
He also beat Johnie Berntsson of Sweden and the 2009 runner up Torvar Mirsky of Australia but, despite topping the table with a 4-0 scoreline immediately went into a de-brief which concentrated on starting. "Our starting has not been good enough and we need to improve because this is a track on which is it always difficult to overtake."
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The "track" is right inside Marstrand Harbour and constitutes a perfect amphitheatre. The sunshine and a westerly breeze of 15 to 18 knots made for perfect viewing, but the restrictions on the right hand side made it tricky to negotiate.
Ainslie ended 2-2 and was not as unhappy as he might have been. "It was a fantastic day for sailing and we had two good races," he said. "We had a frustrating problem with a sail halyard jammer which took us a whole leg to sort out.
"To make it to the quarter finals we almost definitely need four wins out of the seven races, so, with three to go, we are living dangerously."
For Ainslie and crew, including tactician Iain Percy, the plan had been to do only five of the 10 regattas on the world circuit, Marstrand being his second. But he now plans to do all the remaining five, the next of which is at St. Moritz at the end of August.
In the women's event, the British team of Lucy Macgregor, sister Kate and Annie Lush added another win to the three on the first day, but their one loss meant they were still one behind Germany's Silke Hahlbrock, who has a 5-0 scoreline.