The Biancocelesti need a win to seal qualification and with it top spot in Group J, although Spurs know that an away victory at the Stadio Olimpico would secure their own passage into the knockout rounds.
Marchetti was busier than opposite number Hugo Lloris when the two sides met at White Hart Lane in September, and the former Cagliari keeper thinks that Spurs are one of the toughest sides in the competition.
"Tottenham are one of the strongest sides in the Europa League," the 29-year-old told reporters ahead of the game.
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"We will try to win tomorrow [Thursday] in order to secure qualification, but it will be a battle."
Lazio received a confidence boost in drawing with Serie A leaders Juventus at the weekend, but Marchetti played down his team's prospects of having things all their own way as the continental campaign resumes.
The Italian shot-stopper said: "We are enjoying the Europe League [but] it is a competition that many teams have their eye on."