The goalkeeper has praised the leadership qualities of his coach and believes he has a squad of "outstanding" ability at his disposal
Reina teamed up with his Liverpool mentor at the Partenopei this summer and made an immediate impact on his debut, saving Lukas Podolski's penalty and preserving Napoli's first-half advantage.
And despite seeing the Gunners pull two back in the second period, Reina believes the ambitious Serie A outfit are on the right track under Benitez.
"I've found a group that works well, an outstanding squad that is very well led by Benitez," the custodian told reporters after the match.
"I'm glad to have found Benitez here, being part of an ambitious project and to be able to compete in the Champions League.
"We performed well in a difficult stadium and intense match today. I'm happy about the penalty save but especially happy for the team and the good result."
Benitez also expressed his satisfaction with the result after seeing his men surge into the lead, in an encounter which also saw former Arsenal target Gonzalo Higuain make his debut.
"Reina is a player of the highest level, and like the others who arrived will improve again," the Spaniard continued.
"We lacked intensity handling the ball when Arsenal pressured us in the second-half, but it was a good game, and we showed what we can do.
"Napoli is a team that wants to grow, we are all working to improve. Napoli are great in Italy, and we want to work so that she may also become strong in Europe."
The San Paolo outfit finished second in Serie A last season and wasted no time in reinforcing, with the likes of Higuain, Jose Callejon and Raul Albiol arriving after the €60 million sale of Edinson Cavani.
Napoli will now face Porto in their subsequent fixture on Sunday.