Semi-finalists in Europe's elite club competition in 2006, injury-ravaged Villarreal have lost all five matches this time but Mazzarri is not expecting an easy ride as his side bid to clinch second place and a spot in the last 16 with a win at the Madrigal.
Bundesliga club Bayern Munich are through as group winners with 13 points, Napoli have eight in second and Manchester City are third with seven.
"Villarreal have had very bad luck in this Champions League and on paper they have nothing to play for," Mazzarri told a news conference.
"But they have their pride and their footballing values and all their players will be entering the field wanting to win the game," he added.
"Villarreal are a very organised team and, despite their multiple injuries, I am sure they will go out on the pitch determined to beat us.
"We must think only of our match, must focus on our game and our way of playing football and ignore everything else."
Villarreal coach Juan Carlos Garrido said a strong performance was crucial to lift morale as the Spanish club attempt to put their Champions League failure behind them and reverse a poor run in La Liga.
"Napoli are trying to qualify for the next stage but our objective is dignity," said Garrido, whose team have lost their last two La Liga games and languish in 15th place.
"If we play a great match we will come away stronger because we are contesting the strongest group in Champions League history," he added.
"We want to exit this season's competition with pride by beating a magnificent team.
"It's an important game for us because of what it signifies. We have to try to win for our own good."
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