Jose Callejon's 81st-minute strike was enough to clinch three points for Napoli and seal a second win inside a month over their opponents, following a 3-0 Coppa Italia success in February.
The win all but ended the Serie A title race, but massively boosted Napoli's hopes of leapfrogging the men from the capital into second - the final automatic UEFA Champions League qualifying spot.
Benitez, who managed Reina at Liverpool, took time to praise his goalkeeper, who has kept six clean sheets in his last 11 outings for the San Paolo club.
"The truth is that I know him well," Benitez told his official website. "He has been with us at Liverpool and now here in Naples.
"When you are in excellent physical condition as I think he is now, the excellence shown highlights to me him as one of the best goalkeepers in the world.
"When we were together in the Premier League, I considered him the number one in the world and had not the slightest problem to publicly say it because I thought it.
"I know what he can offer and how he can help us to achieve our challenges and our goals."
Higuain moved from Real Madrid at the start of this season and has 20 goals in all competitions, leading Benitez to highlight the Argentinian as one of Napoli's most important figures.
"He has done a tremendous job," he said.
"He has opened many spaces, works continuously for the team and for example in the attacking phase, has made a perfect move for me which was key in resolving the game.
"Gonzalo can always make a difference with his contribution between winning and losing."
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