Concord started brightly and dominated the opening half hour, before Harlow began to find their feet. The home side did produce some sparks of quality, but despite creating some chances they weren't able to get on the scoresheet.
The visitors scored after three minutes when they broke down the left and squared for Ben Greenhalgh to finish well past Ed Thompson.
The score was then doubled on 19 minutes when Tony Stokes rose unmarked to head home a corner, before he scored again three minutes later. He latched onto a through-ball to calmly slide the ball home.
Harlow created chances late in the first half, but it was Concord again who scored early in the second period. Louis Taaffe received the ball on the edge of the area, and cut inside before drilling a low shot into the bottom corner.
The scoring was complete on 86 minutes when former Harlow player Bertie Brayley was in the right place at the right time. The ball had rebounded off the post and fell nicely to the striker who tapped home from close range.
It was a difficult afternoon for the Hawks against the Vanarama National League South side, but despite the scoreline there were moments of positivity which will give boss Danny Chapman food for thought as the league campaign draws closer.
The next pre-season friendly for Harlow is an away trip to Hertford Town on Tuesday 21st July. Kick off is at 7:45pm.