After slipping down to fourth following a poor run, PSG have won their last two Ligue 1 games 4-0 and will go top if they win their home clash with leaders Olympique Lyon on Sunday.
"Reaching the winter break in first place will play on everyone's mind," Menez told a news conference.
"It will be our chance to prove we are back on top. We know that if we all make the efforts needed, there will not be any problem.
"We are not invincible, you must not exaggerate. But the truth is that we will be very hard to beat if we keep on putting all our forces together. And we know we can do even better that we have done," added the former Roma player.
The Qatar-backed side had been expected to dominate the league after spending over 100 million euros on transfers during the close season. Instead, they found themselves under fire for a lack of consistency.
But they have displayed impressive collective strength in recent games after coach Carlo Ancelotti switched from a 4-3-3 formation to a 4-4-2 with two players on the wing.
"I said before the season started that we would be our main enemy," said Menez. "We have realised that it is not enough to just put 11 players on the pitch, even ones with great records, to win matches. Everybody moved on and it has paid off."
Lyon could only draw 1-1 against strugglers Nancy in midweek and the trip to Paris will be all the more challenging for a side decimated by injury.
Full-back Anthony Reveillere and forward Alexandre Lacazette were both replaced after picking injuries in the first half and are doubtful for Sunday's clash.
Lyon will be without midfielders Clement Grenier and Yoann Gourcuff, who were ruled out until January with thigh problems.
Third-placed Olympique Marseille, tied on 32 points with PSG, could also catch Lyon if they win at mid-table Toulouse on Saturday.
The Southerners, who have alternated wins and losses in their last six games, hope they will find consistency at last.
"We always react. We are crushed at home then we take points away. But we can't continue with this roller-coaster series," coach Elie Baup told the club website.
