After a bruising encounter at Claremont Road, the tension in the opening exchanges was palpable.
Fiston Manuella had won the midfield mind games after eight seconds at Claremont, and former Wales international and Aldershot captain Darren Barnard was not going to let that happen again crunching Manuella with his studs up in the first minute.
The contest remained niggly throughout but was intertwined by some exquisite football by Chelmsford and good counter attacking play by Aldershot.
The Clarets played like the home side throughout the first half and created the first opening on 13 minutes.
Ricky Holmes was played clean through but he was thwarted by a superb Nikki Bull save.
Chelmsford dominated possession and John Grant nearly put the Shots ahead on 32 minutes.
Mark Molesey's well-weighted pass put the former Halifax striker through on goal. He drove from eight yards and Richard McKinney got down well but still required a goalline clearance from Chris Duffy to avert the danger.
Mario Noto should have put the Clarets ahead on 41 minutes. Holmes combined well with Kezie Ibe creating time and space for Noto seven yards out but he blazed woefully over.
Aldershot broke the deadlock in the 52nd minute with a penalty after a Steve Ward handball. Bernard showed his experience by calmly firing into the bottom corner.
The second half lacked the intensity of the first and Chelmsford had the best chances but lacked penetration.
On 63 minutes Holmes went on a mazy 30-yard run but shot straight at Bull. Then on 76 minutes Moto jinked past Williams and Molesey but shot weakly at Bull.
Two minutes later Marcus Gayle came agonisingly close to finishing the contest.
Williams drove 40 yards down the left flank and crossed to the back post. The former Wimbledon striker just made contact with the ball but it rolled inches wide of the far post.
Looking far stronger as the game wore on, the Shots booked their place in the second round on 80 minutes.
Louis Soares made space for himself inside the penalty area. He cut the ball back to Grant and he made no mistake from four yards and set up an interesting tie against Conference South strugglers Basingstoke.