The in-form striker has topped the Premier League scoring charts after bringing his tally to 12 goals.
"Anelka has been, and is, the savior for us at the moment with Didier having been out and only just coming back from injury," Terry was quoted by skysports.com as saying.
"For me Anelka is in the best form of his career. He is getting the goals as well and is top scorer in the Premier League and long may it continue."
The towering forward has Joined Luiz Felipe Scolari's men last season from Bolton Wanderers.
"When we signed him I said thank God you are here because I used to hate playing against him," Terry said.
"He was always playing on my shoulder and he's a great finisher as well."
The 29-year-old compensated for the loss of hitman Didier Drogba, who didn't feature for the Blues on a frequent basis this season due to injury.
Favorite Position
The English defender believes Anelka prefer to play in the midfield alongside Florent Malouda, Salomon Kalou and Joe Cole.
"He relishes playing down the middle. He relishes the likes of Flo (Malodua) and Coley and Salomon Kalou on either side of him," Terry revealed.
"It gives him the chance to play in between the two centre-halves and on the shoulders of them because the two opposition full-backs are getting stretched all the time by the wide men."
Anelka helped the London-based side outclass West Bromwich Albion 3-0 in the Premier League last Saturday.
"We soaked up a lot of pressure from West Brom early on and hit them on the counter-attack with three goals," concluded Terry.