كتب : Omar AbdelAziz
The Blues are just two points adrift of their London rivals, and Terry believes that last weekend's 4-4 thriller at Tottenham put them under pressure to win at Stamford Bridge.
"We have to win, Sunday's a must-win game now. No question," he told the Daily Mirror.
"If we had beaten Spurs, maybe we could have afforded to draw against Arsenal but not now. We are at home and there's added pressure on us to win."
Terry is wary of his opposition's abilities, but is confident that Chelsea have their own ways of winning.
"When Arsenal really turn it on, they're exceptional," he added.
"When Adebayor is flying and Fabregas is bombing on from midfield with those fantastically timed runs of his, they have got goals in them. But there have been plenty of times when they haven't been able to kill games off.
"When it doesn't go well," sometimes you need a scrappy goal, a deflection from inside the box, everybody hurling themselves at the ball.
"Ourselves and Man United, we've got that, but Arsenal don't seem to get goals like that. It's a weakness in them."
The Gunners are winless in the last four games and another slip could well see them go off the title race.