Terry shocked English football on Sunday when he retired from international football ahead of this week's FA tribunal into allegations that he racially abused Queens Park Rangers defender Anton Ferdinand last season.
The 31-year-old, acquitted in a law court in July of racial abuse, said his position in the England setup was "untenable" because the FA were pressing ahead with the hearing.
He shrugged off the extra attention when he featured in Chelsea's 6-0 League Cup romp on Tuesday against Wolverhampton Wanderers, but London rivals Arsenal will provide a bigger test of the defender's resolve.
Terry will need to be at his most focused if Chelsea's unbeaten start remains intact against Arsenal, one of three other top-flight teams yet to lose five games into the season.
"This is the first actual big game for us this season. Our performances and quality - we know how it is. But we have to show everyone and we have to show it every game," said Serbian defender Ivanovic.
Chelsea have yet to play a title rival and have made the most of an inviting start to the Premier League season, racking up wins against Wigan Athletic, Reading, Newcastle United and Stoke City as well as drawing with QPR.
They were not totally convincing in a 2-2 Champions League draw at home to Juventus and Arsenal offer a similar threat after an impressive showing in a 1-1 draw at champions Manchester City last weekend.
"This is the biggest challenge. I think Arsenal will be a great challenge for us, and we have to really be ready for that," added Ivanovic.
Terry had a woeful time against Arsenal in last season's first league encounter between the pair, slipping to gift Robin Van Persie a late goal and the lead from which Chelsea never recovered in the 5-3 rollercoaster ride.
Assistant manager Eddie Newton said the robust defender was in a good frame of mind despite spending a chunk of his week at the FA hearing at Wembley Stadium.
"We've been talking to John to see what his mindset is and he's been very positive and upbeat. He's been dealing with the situation at hand," Newton told reporters on Tuesday.
STUMBLING CITY
While Chelsea are buzzing following their promising start to the season and their League Cup confidence boost, champions Manchester City stumbled out of the same competition on Tuesday.
City are also unbeaten in the league but three draws from their opening five games and some defensive lapses have left manager Roberto Mancini with a furrowed brow.
They travel to Chelsea's in-form neighbours Fulham on Saturday hoping to rediscover the winning habit after the 4-2 extra time defeat in the League Cup by Aston Villa.
"The second year after winning a championship is always difficult and I hope we start to win in our next league game, because we need a win. But we need to improve if we are to do that," said City manager Roberto Mancini.
Manchester United have also failed to hit the hei
