The 27-year-old military officer was in pole position after the opening fencing phase only to be knocked off the summit after the 200m swimming freestyle by China's Cao Zhongrong who endured a nightmare jumping round, picking up 120 penalty points after knocking six fences down.

In third going into the concluding combined running and shooting leg was Russia's world champion Aleksander Lesun, with Hungarian Robert Kasza in fourth.

The points from the first three legs are converted into time to determine the staggered start for the running/shooting finale.

Cao will start one second behind Svoboda, with Lesun a further eight seconds back.

Lesun's compatriot, Andrei Moiseev who is seeking a third consecutive Olympic title, is placed sixth overall and will start 16sec behind the leader. The show jumping contest represented a true test of horsemanship for the 35 athletes - China's Guan Wang having pulled out with injury - who had to partner unfamiliar horses drawn by lots.

Competitors were only given 20 minutes to get to know their equine 'blind dates' before setting out on their rounds.

Some, like Svoboda, got on fine - others, like Woojin Hwang who was unseated when his mount reared up at the start, were less fortunate.

London 2012 organisers were keen to improve the standard of horse available after complaints were made about the quality of mounts at the modern pentathlon evennt in Beijing four years ago.