Five first-half goals saw the Lilywhites take a commanding lead, and although Lee Murtagh pulled one back for Shels, there was only going to be one winner at Tolka Park
It didn't take long for Dundalk to replicate their league form, taking the lead after just 13 minutes after fine interplay between Richie Towell and John Dillon, with Towell putting the ball past Niall Burdon. Five minutes later, the Lilywhites doubled their lead as Andy Boyle headed in a Darren Meenan corner.
Dundalk's third saw Towell unselfishly lay the ball off for Pat Hoban as Burdon closed him down, while Shels began to grow visibly frustrated. The fourth goal was an ambitious effort from Kurtis Byrne from near the half-way line as he spotted the goalkeeper off his line, while Towell grabbed a second in first-half stoppage time from John Sullivan's cross.
Five minutes into the second-half, Shelbourne bagged a consolation goal as Lee Murtagh picked up Sean Brennan's pass to score from the edge of the area. Dundalk seemed happy to sit on their lead as the match lost its impetus following Shels' goal, but the hosts did go close again as Peter Cherrie was forced into a good save from Darren Tinnelly with a quarter-of-an-hour remaining.
Dundalk will now be brimming with confidence ahead of their top of the table tie with St Patrick's Athletic next weekend, particularly after the Saints' struggles against Shamrock Rovers knocked them out of the FAI Cup.