Carlo Ancelotti’s side looked to have ended the Gunners' title hopes after completing a league double over the north Londoners in February.
But Arsenal have gone on to win 18 points out of 18 since that match. With Chelsea dropping points from winning positions three times in the same period, that advantage has been cut to just one point.
“When we beat them in November we were 11 points clear and I wrote them off. But fair play to them, they have had a few players out with injury and have a fairly young side," he said in the London Evening Standard.
“But they're difficult to play against when the lower teams go to the Emirates. It is such a big pitch and the way they play, it's difficult for the lower teams to deal with them. Against the big sides they can lose those games because there is not a big difference between the big teams at all.”
Arsenal find themselves only two points off top spot despite having lost four out of four against their title rivals Chelsea and Manchester United.
However, with these games out of the way Arsene Wenger’s men face a less daunting run in than the Stamford Bridge outfit, who still have to travel to Old Trafford, Anfield and White Hart Lane.
Terry is aware though that Chelsea need to pick up their game against sides outside the top four if they are to regain the title.
“We have done a bit better in the big games this season but have dropped points in games we should have won.
“It's going to go right to the wire and we're looking to keep going right to the death. It is important as a group of players to focus on one game at a time.”
Chelsea face Aston Villa at Stamford Bridge on Saturday, a fixture the Blues have found difficult in recent seasons, winning only five of their last 15 meetings.
Ricardo Carvalho’s addition to Chelsea’s growing injury list leaves the club with only two recognised centre-backs, while Villa have just Nigel Reo-Coker sidelined.
Michael Ballack and Hilario have both returned from the sidelines and could feature. A win would see the west Londoners return to the top of the Premier League for a few hours before Manchester United’s late kick-off against Bolton.
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