"Our manager knows Ronaldo very well," Terry told the Sunday Mirror. "And Ashley Cole always seems to do very well against him.
"Ronaldo doesn't play that well when he's facing Ashley at the top of his game. So were hoping that Ashley nullifies the threat of Ronaldo."
As for United's £32 million transfer deadline day acquisition Berbatov, though Terry rates the player highly he believes Chelsea can cope with his threat.
"Berbatov is a world-class player," Terry added. "It's up to Ricky Carvalho and me to stop him, but Berbatov can disappear from games at times.
"If we can shield him out of the match it is bound to be to our advantage."
"It's a must-win game for them, but a good time for us to be facing them in the form we are in," Terry went on. "They certainly can't afford to lose this one and allow us to open up a substantial lead on them even at this early stage.
"I know we haven't seen the best of United yet by any means. And there's no doubt in my mind that they will go on a run and get back in the frame.
"But if we do manage to win its down to us to keep going. If we can do that well make it difficult not just for United but for the other teams around us.
"Last year when United were playing well we kept winning and we weren't getting any closer to them. If you're the team in front and you keep winning its difficult for anyone to catch you."