The game kicked off in torrential rain at Dark Lane but the young Hatters made light of the conditions with an early goal.
James Vincent opened the scoring after just nine minutes when he burst clear of the Rossendale defence and finished clinically.
A minute later it was almost 2-0 but the Martin Middlehurst made a great save to deny Danny Pilkington's 20-yard curler.
Pilks didn't have to wait long for a goal, though. Receiving a clever pass from Oli Johnson he squeezed the ball past the Middlehurst from a narrow angle.
The UniBond outfit pulled one back on 34 minutes when Marcus Calvert cut in from the left and hit a powerful drive into Jason Astbury's top corner.
The two goal advantage was restored soon after, though, when Tom Clarkson turned Pilkington's left-wing cross past his own goalkeeper.
Astbury was called into action twice in the closing stages of the first half when he saved well from Calvert and then produced another good stop to deny former County star Dan Ellis.
County had a let off after the break when the dangerous Calvert hit a dipping shot that clipped Astbury's crossbar before bouncing behind.
That apart, the Hatters were always in control and they were desperately unlucky not to add a fourth when Johnson was harshly adjudged to be offside after he side-footed home following a brilliant four-man move.
County did make it four in the closing stages when Neil Holmes crossed to Paul Ennis who scored at the far post.
County: Astbury (Bell); Halls, S Barnes, J Thompson, L Barnes (Jackson); Turnbull, Dicker (Green); J Vincent, Pilkington, Johnson (Holmes); Ennis.
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