Former Clarets defender Paul Rodgers almost opened the scoring for Harlow Town with a stunning volley, but his effort after just two minutes flew narrowly wide.
Shortly afterwards, the visitors began a period of dominance and Harlow rarely threatened afterwards.
Rhys Murphy controlled well outside the area under pressure but, after poking beyond Town ‘keeper David Hughes, the striker’s effort was ruled out for offside. Moments later, Tom Wraight drilled a left-wing cross to Scott Fenwick. The City striker knocked the ball onto his left foot but his fiercely struck shot was palmed over the bar by Hughes.
On 13 minutes, the Clarets finally broke the deadlock. A defensive error from Rodgers allowed Murphy to drive forward, he passed the ball across to Fenwick who - with an open-goal - tapped it home.
Five minutes later, Murphy changed from provider to goalscorer as he rounded past Hughes before sliding the ball across the line from a tight angle.
After 26 minutes, the Clarets were forced into an early change as Elliot Omozusi suffered a knock to his ankle. Then, a minute before the break, Murphy was substituted following a heavy challenge on the by-line, adding further difficulties to City boss Rod Stringer’s selection dilemma.
Early in the second half Charlie Edwards created a promising chance for the hosts, but his left-footed shot lacked substantial power.
Jai Reason came close to adding a third for City, but his curling effort went agonisingly wide of the post.
The hosts had a golden chance to claw themselves back into the game when they were awarded a penalty, but Ross Worner guessed correctly and saved Andrew McCollin’s left-footed spot-kick.
Rob Swaine almost scored his second goal of pre-season with a strong volley, but it was blocked well inside the area.
As City went searching for further goals, they came close when Wraight crossed into the area - but new signing Jordan Chiedozie tapped past the post from six yards out.
But Chiedozie made amends for his earlier miss five minutes later, curling home from the right side of the area to give City a three-goal lead.
Wraight wrapped up proceedings late on in the second half as he fired home City’s fourth in added time.