Benitez succeeded McClaren as Newcastle boss last week, overseeing a 1-0 defeat at Premier League leaders Leicester City during his first game in charge of the Tyneside club.
But Merson feels the performance at the King Power Stadium was an improvement on the previous regime, citing the players’ willingness to get on the ball and make themselves available a key difference.
“He’s already transformed them. Under Steve McClaren the Newcastle players all looked petrified of getting on the ball. They were hiding. I like Steve. He’s a top drawer coach. He’s just not a manager in my opinion. They are two very different things,” Merson explained.
“It’s all changed for Newcastle now. They looked a completely different team against Leicester and he only had a few days to work with them.”
Newcastle may have lost at Leicester, yet many supporters and observers alike thought the performance as a vast improvement on recent weeks and tactically the Magpies looked in good shape.
This weekend the challenge facing them couldn’t be any bigger as they look to defeat North East rivals Sunderland for the first time in seven appearances and the first since 2010.
The two relegation-threatened clubs are separated by just one point, and victory for either at St. James’ Park on Sunday will go a long way to helping preserve their top-flight status come May.
Benitez isn’t a renowned motivator, yet tactically he is as astute as they come and he will be reviewing the tapes and telling his players exactly how they can pinpoint Sunderland’s weaknesses on Sunday.