A scintillating time of 1:49.62 in the 200m freestyle swim gave the Brits an early lead but they dropped to sixth after 14 wins and 18 defeats in the fencing salle.
The ride was described by Pentathlon GB Performance Director Jan Bartu as “carnage” as the use of new horses led to a host of problems, particularly in the early stages.
“The boys had a good opportunity to gain an advantage but unfortunately they knocked down four poles when they could have got away with just one,” Bartu added. “This didn’t put them in a good enough position ahead of the combined event.”
They started the run/shoot in 11th position, 81 seconds behind leaders South Korea but just 21 seconds outside the medal places.
A thrilling combined event ensued with Sport & Exercise Science student Toolis and Sport Performance graduate Evans firmly among the competing pack before eventually finishing ninth.
Toolis will be competing again on Thursday in the men’s individual qualification alongside Jamie Cooke, Joe Choong and Sam Curry.
Wednesday sees women’s relay silver-medallists Joanna Muir and Samantha Murray compete in the women’s individual qualification along with Kate French and Freyja Prentice.