"It was just one game," the Dutch veteran said of the demolition of the Czechs, ahead of a final training session in Warsaw's National Stadium, where Poland and Russia meet on Tuesday for one of the most politically-charged clashes of the tournament.
With Poland only managing a 1-1 draw with Greece in their own opening game in Warsaw on Friday - despite the vocal support of tens of thousands of home fans, or perhaps due to that pressure - Tuesday's match is crucial for the Euro 2012 co-hosts if they want to keep their hopes alive.
"Poland are a very strong team and they're playing at home, which is an advantage. But we showed in the first game that we're a very good team and we can make it very difficult for our opponents," said Advocaat.
"Poland and Russia are going to go for a win, and only during a game can you say if that's realistic or not."
Pundits see Russia as shoo-ins to top Group C favorites after the result against the Czechs in the southwestern Polish city of Wroclaw on Friday.
"That's very optimistic. We've only played one game, so we'll see how it goes"
"This first game was one to win of course, but we'll see what happens."
"We've got three points," he underlined.
After Poland, Russia wrap up their group campaign against Greece in Warsaw on Saturday, while the Poles face the Czechs in Wroclaw.
Tuesday's match has a fiercely political context, with Poland and Russia's sporting rivalry feeding into centuries of bad blood, and Polish media have been banging the drum as the game looms.
Journalists were warned not to ask about off-pitch issues, including fears of hooliganism after clashes between Russian fans and Polish stewards following the game with the Czechs.
"We said at the start that we're not going to talk about politics, only the game, so I'm not going to answer that," Advocaat snapped when pressed to comment.
UEFA is also probing claims of racist chants by Russia fans against Czech player Theodor Gebre Selassie, who is black.
Asked whether concern about racist fans were making waves in the Russian dressing room, Advocaat and Zyryanov sat in silence.
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