It's the fourth successive year that K's have played at home on the first Monday of the season and those four games have produced no fewer than 27 goals.
By those standards tonight's game got off to a slow start: it was 15 minutes before Simeon Akinola put the visitors ahead.
Dan Lodge replied three minutes later with a penalty after Andre McCollin was fouled.
Both sides had plenty of chances in the rest of an even and exciting first half but K's gained the upper hand after the restart.
McCollin met an accurate cross from Charles Ofosu-Hene with a splendid header to put K's ahead in the 53rd minute.
In their next attack Jamie Jackson pulled off an athletic save from Lodge but in vain, as the resultant corner found its way to Aaron Goode 20 yards out and he fired the home side into a 3-1 lead.
Jackson made several other top-class saves before pulling down the dangerous McCollin in the 75th minute, allowing Lodge to convert another penalty.
Harrow pulled one back in the 90th minute thanks to a free-kick near the halfway line from Gary Jones which everyone missed.
Home keeper Rob Tolfrey was left somewhat red-faced by that but he was at his best to deny Jones another moments later, saving K's from what could have been a worrying final minute or so.