The Portuguese has shown his qualities since arriving in North London early last season.
While Spurs have endured some setbacks under Mourinho, they are currently joint top of the Premier League with Liverpool after 9 games.
"He's found a way with the group of players he has," Sherwood told talkSPORT.
"He's bought very well, [Sergio] Reguilon has been a good signing at left-back, but [Pierre-Emile] Hojbjerg for me has been the best signing. He fits into the style and just protects the two centre-halves.
"Jose has brainwashed his players to believe they have to work to achieve something – they need to win trophies, this group of players.
"When you play as solid as they do, he's almost brainwashed them into believing.
"And why wouldn't you believe in him? He's won 20 major trophies in his career and you're winning football matches, so then you start believing that this guy is the real deal, he knows what he's talking about, and why can't we win the league?"