China's Qian Zhenhua led after two rounds of the men's Olympic modern pentathlon heading into Friday as the medal table-topping hosts eyed yet another gold in Beijing.
Qian, second after the initial target shooting phase, scored 1,024 points in the fencing section. That left him with a total of 2,228 points, 36 ahead of defending Olympic champion Andrey Moiseev of Russia.
Both men recorded 26 wins and nine defeats in the fencing section but Qian's better shooting gave him the lead.
David Svoboda of the Czech Republic, the first round leader, was 12 points behind Moiseev in third place.
Svoboda scored 191 out of a maximum 200 in the shooting, surpassing the previous Olympic best of 186 shared by the Belarus duo of Pavel Dougal (Sydney 2000) and Dmitry Meliakh (Athens 2004).
The Czech was runner-up in this year's world championships, held in May and June. But the man who beat him, Russia's Ilya Frolov, was down the Olympic field in 15th place.
Moiseev is bidding to become the first man since Lars Hall of Sweden in 1952 and 1956 to win successive Olympic modern pentathlon titles.
Created by the French founder of the modern Olympics, Baron Pierre de Coubertin, the modern pentathlon is a demanding event featuring five disciplines based on the abilities that might have been expected of a soldier in the army of Napoleon.
In its present format, which takes place over one day, the initial section sees the 36 competitors given 20 shots from 10 metres with a pistol at a 155mm diameter target.
In fencing, they have a one-minute bout with every other competitor in the epee event, where hitting any part of the body counts. The swimming is over 200 metres, or four laps of a pool, in heats depending on previous results.
The show-jumping is a 400m course with 12 fences, although the toughest part is that the athletes are on horses they've never ridden before, their mounts chosen by lottery.
Then the final 3,000m run is staggered with the leader starting first - a three-point lead is a three-second advantage - meaning the first to cross the finishing line is the winner of the overall competition.