"It didn't make sense to train hard so they wouldn't be able to run any more," the Dutchman told reporters. "We did look at our health and you see the benefits it reaped."
Russia swept to an impressive victory with a slick counter-attacking display and some clinical finishing to take eary control of what was predicted to be a tight group. Co-hosts Poland drew 1-1 with Greece in the earlier group game in Warsaw,
Alan Dzagoev scored either side of a dinked effort from Roman Shirokov before substitute Roman Pavlyuchenko struck a brilliant fourth to sink their dazed opponents.
Despite the impressive performance, Advocaat said Russia could have been sharper in front of goal.
"Four goals in an international tournament is quite a lot," he said. "We actually should have scored more goals. There were moments when we could have been sharper."
Czech coach Michal Bilek rued that his side could not capitalize at the beginning of the match when they were able to press Russia, only to be let down by glaring mistakes at the back.
"This result is very impressive for Russia," he said. "The Russians have great technique and they showed us today they are a very strong team."
Despite the setback, Bilek said his team were capable of shrugging off the heavy defeat and would bounce back in their remaining group games.
