The battle lines were drawn from the start and Ben Ainslie was put on notice that his attempt for a fourth consecutive gold medal was no gimme, but two second places in his opening pair of races under the glittering sunshine of Weymouth Bay also served their own clear warning.
In both he had to overcome setbacks. In both he put on a display of strength and fitness and the mature Ben Ainslie, he is now 35, put in a the sort of solid start that has eluded him in earlier big encounters,
"It was a good start, but there is a long way to go," he said, clearly showing what a physical test the fresh breeze and short chop had provided for the men's heavyweight singlehanded dingy, the Finn.
He also had mixed feelings about the opening race on an inshore course where a spectator area allowed Olympic sailing to become a turnstile paying event for the first time.
"It was an amazing feeling to hear that crowd cheering you on," he said, explaining that by having the racecourse so close to the shore the conditions were even more tricky than in the rest of the bay.
"Compared with my last Olympics it was nice to get two solid results," he said. In China four years ago he was recovering from mumps, and in Athens, in 2004, suffered an early race disqualification.
The medals are decided by a series of 10 races, from which the top 10 go forward, carrying their accumulated points, to a double points-scoring decider.
He was quick to pay tribute to the man who beat him on this opening day and beat him twice. Jonas Högh-Christensen was on fire –"he sailed really well and got away", said Ainslie. The Dane led at every mark rounding in both races and seems determined to recapture the heritage of his great predecessor, Paul Elvström.
Elvström remains the most successful sailor in the Olympic Games, with four gold medals. If Ainslie wins in Weymouth he will match that and move ahead as he also won a silver medal in the Savannah sailing venue for the Atlanta games in 1996.
He had missed gold after being narrowly beaten by Brazil's Robert Scheidt and went on to exact ruthless revenge four years later in Sydney.
On that famous harbour, Ian Percy was dominant in the Finn and in China, with crewman Andrew Simpson, pipped Scheidt for the gold in the Star keelboat class.
They have been at each other's throats ever since. In their opening race Percy had the better of the first half but faded in the second to 11th while Scheidt recovered from a poor start to finish fourth.
In the second, they were given the same finish time, but the spotters decided that Scheidt had a centimetre or two of advantage to make him first, Percy second.