The Brazil international scored the winning goal for the second week running as he helped PSG claim a three-point lead at the top of the Ligue 1 table.
Despite being surrounded by four defenders, Neymar found space to shoot in the 87th minute before finding the back of the net.
After netting the winner against Strasbourg with an overhead kick, Neymar has now started to find his magic touch after missing the first five games of the season.
The former Barcelona ace tried to force a move back to Camp Nou in the summer and PSG fans have booed him during the last two matches.
Tuchel is confident he will remain committed until the transfer window reopens in January, even though fans are still concerned.
"He is 100 per cent with us. He is 100 per cent in the squad - he laughs and jokes and is reliable," Tuchel told a news conference.
"He is totally there with his team-mates. That is normal, as well as necessary. He is a very sensitive guy. This is only his third match in four months.
He will gain in physical capacity with the matches, and this will help him. Neymar is always decisive, he is always creative, and he looks ahead."
Since losing to Rennes on August 18, PSG have since won five games in a row in all competitions.
They beat Real Madrid 3-0 in the Champions League last week and they are back in action in Europe on October 1 when they travel to Turkey to face Galatasaray.