Alistair Brownlee and younger brother Jonathan were one-two in the world last year. The host country has invested heavily on a repeat in Hyde Park.
"The British have played this to an almost checkmate," Canada's Simon Whitfield says. "They have a team. They have the two best guys in the world and they have a team racer.
"Every guy in this race is trying to figure out the way to avoid this checkmate. We are trying to figure out a way to parlay that final pawn into a queen to knock out the king."
Whitfield, of Kingston, Ont., was the Olympic champion in 2000 and added a silver medal in 2008. He'll be one of just two men Tuesday to have raced in all four Olympic triathlons to date. Hunter Kemper of the U.S. is the other.
The Brownlee brothers, Javier Gomez of Spain, Svein Riederer of Switzerland, Richard Murray of South Africa and Alexander Bryukhankov of Russia are considered favourites ahead of the 37-year-old Whitfield, but the Canadian is always a compelling racer to watch.
Kyle Jones of Oakville, Ont., is on the edge of the world's elites. He won a World Cup race in Edmonton last month.
Victoria's Brent McMahon was hobbled by injury when he competed at the 2004 Olympic in Athens. He raced 20 times over the last year to gain the third and final Olympic berth for Canada.
The Canadians will have to be as bold as the Brits, according to Jones.
"With the Brownlees, we can expect what we've seen already," he said. "They're among the best swimmers, best cyclists, best runners and they race with no fear.
"If you want to have any chance at beating them, you've got to go with them. If you can put yourself in contention in the swim and the bike, which I think we should be able to do, all three of us, it's going to come down to the run."
Also Tuesday, track cyclist Tara Whitten of Edmonton sits fourth heading into the second day of the omnium, which is new to the Olympics. The six-race event concludes with the individual pursuit, scratch race and time trial.
Diver Alex Despatie of Laval, Que., will continue to look for his third career Olmypic medal in the semifinal of the men's three-metre springboard. Despatie qualified ninth, while Francois Imbeau-Dulac of St-Lazare, Que., qualified 12th.
Synchronized swimmers Marie-Pier Boudreau-Gagnon of Riviere-du-Loup, Que., and Elise Marcotte of Quebec City are also fourth heading into the duet final, in which the duo will again perform their "Jester" free routine.
At the track, Derek Drouin and Michael Mason are in the men's high jump final. Also watch for Jessica Zelinka of London, Ont., Phylicia George of Markham, Ont., and Nikkita Holder of Pickering, Ont., in the women's hurdles semifinals.
Custio Clayton of Dartmouth, N.S., is up against home-country favourite Freddie Evans in a welterweight boxing quarter-final. The women's basketball team takes on defending champion U.S. in a quarter-final.
Nikola Girke of West Vancouver, B.C., and Vancouver's Zach Plavsic compete in the women's and men's windsurfing finals at Weymouth.
Note to readers: This is a corrected story. A previous version had Despatie advancing to the 3-metre semifinal.Suggest a correction