Chelsea will face former manager Andre Villas-Boas when they travel to White Hart Lane as league leaders and the defender believes that the game will be decided by "small details"
Andre Villas-Boas will meet his former club for the first time at White Hart Lane on the back of four consecutive league victories.
Chelsea, meanwhile, have won their last three top flight matches and sit four points clear at the summit of the table having collected 19 points from their opening seven games.
"The international break is a good time to enjoy this first position but there is a very important period coming for us with very tough games, and this is going to be a great challenge for us," Ivanovic told the club's official website.
"It is always very difficult to play the game after the international break but especially when you play a big derby, this is very tough for us.
"Our games before against Tottenham were very interesting, very hard, very tough for both sides, but especially now with our ex-manager there it is going to be difficult in one way, but in the other way we know what his ideas are and what we can expect from them. This game is going to be decided by small details."
Ivanovic has excelled as a more attacking full-back so far this season, having scored three goals in the Premier League to match the tally he managed during the entire 2011-12 campaign.
The Serbia international's latest strike came in the final 15 minutes as Chelsea saw off Norwich City in a 4-1 home victory.
"At the moment I feel physically ready and that I can go forward a lot," he explained. "But my goal on Saturday to be honest didn't decide the game and the most important was the three points. It is good at the moment when the whole team is doing well.
"We didn't start the game like we expected and it was a good reaction by the whole team, we kept going and we equalised as soon as possible and after that we changed the game. This short period, the first and second goals, decided the game."