Tevez has unsurprisingly been a key figure for Juventus in their quest for a fourth successive Serie A title and has also helped the Italian champions secure a place in the last 16 of the UEFA Champions League.
The former Manchester City striker has 13 goals to his name in all competitions this term, but heads into Monday's meeting with the Coppa Italia winners in Doha with coach Allegri conceding that the Argentina international is not 100 per cent fit.
Despite his fitness issues, Allegri has backed Tevez to once again play a pivotal role as Juve seek to add another trophy to their cabinet.
"We secured our first target of the season by qualifying for the Champions League last 16," Allegri said. "Now it's time for our second target. The Super Cup is a tournament we all want to win.
"I don't think Napoli's only aim is to lift the Super Cup. I think they'll try to get back into the title race if possible, or if not battle for third place, which I think is an important target for the teams in the mix. It gives you a place in the Champions League play-offs.
"Tevez made the difference for us in the first six matches and a Champions League game at home to Malmo. He scored a lot of goals and played a key role throughout games.
"He's clearly not 100 per cent fit at the moment but he's such a big player he can still make the difference at any time. How do I manage him? We're off on holiday on Tuesday so he'll have eight days' break [after the clash with Napoli]."
While Tevez is considered fit enough to play, Juve will again be without Andrea Barzagli (Achilles), Kwadwo Asamoah (knee), Romulo (groin) and Martin Caceres (thigh) for a meeting with a Napoli side that ended a four-game Serie A winless run by beating Parma 2-0 on Thursday.
Rafael Benitez's side will be without Michu (ankle), Lorenzo Insigne (knee ligament) and long-time absentee Juan Zuniga as they attempt to end the year on a high.
Napoi have contested the Coppa Italia final and a UEFA Champions League play-off with Athletic Bilbao in 2014, yet Benitez feels Monday's encounter in the Qatari capital is the most important match of the year for his team.
"I always say the next game is the most important and in this case we are challenging for a trophy with Juventus," Benitez told Sky Sport Italia. "At least I can say it's the most important game of 2014."
