The Bannsiders were always in control of the tie against their Newry-based opponents and eased into a 3-0 lead at half time thanks to goals from Jamie Glackin, Curtis Allen and Matthew Shevlin.
Patrick Kelly scored his first-ever goal for the club at the start of the second half before substitutes Aaron Jarvis and James McLaughlin wrapped up proceedings late on.
The home side were leaving nothing to chance against the Mid Ulster Intermediate League side with Oran Kearney picking a strong starting eleven.
Experienced striker Allen made his return to the Coleraine starting line-up for the first time since the Europa Conference League tie against Velez Mostar back in July.
Marty Gallagher came in between the sticks for the injured Gareth Deane.
For Windmill it was a first game since before Christmas after several postponements in the run up to the festive period.
So it came as no surprise that the Bannsiders started the brighter of the two teams.
But they should have done better inside three minutes as the marauding Lyndon Kane beat his man on the right before clipping a great ball to the unmarked Kelly at the back post, but he took too long to make his mind up and lost possession.
The visitors were struggling to get out of their final third as Coleraine dominated the opening exchanges.
Matthew Shevlin rattled the bar from close range on ten minutes after Kelly's low cross was palmed out by Arron O'Hagan.
The stopper was called into action again on 19 minutes as Stephen O'Donnell got on the end of a looping cross from Glackin, but O'Hagan dealt with the header easily.
Just as it looked like Kieran McCourt's side had weathered the early storm from the Bannsiders and the hailstones they fell behind.
O'Hagan found himself stranded out of his goal as he raced out to tackle the onrushing Allen, but the ball fell for Glackin, who produced a sublime lob to find the net despite the efforts of the defenders on the line.
A second goal for the Bannsiders came eight minutes later after more indecisiveness in the Windmill defence as Stephen Lowry managed to win the ball for Allen to finish from close range.
To their credit the visitors were continuing to work hard with Raymond Fitzpatrick ploughing a lone furrow up front, but he was being starved of support whenever Windmill did manage to play him in.
As we approached half time they were punished again though as Coleraine grabbed a third.
Glackin showed a great turn of pace to get past Mark McAteer before pulling the ball back for Allen, his effort rebounded off the post before Shevlin fired in the loose ball.
Allen had the ball in the net again three minutes before the break, but it was chalked off for a foul on O'Hagan.
The stopper made a vital intervention seconds later to divert Josh Carson's cross away from Allen, who was sliding in for a tap in.
The tie was wrapped up on 52 minutes as teenager Kelly notched his first goal for Coleraine.
He finished off a sweeping move after Brown had picked out the run of Allen, who squared for Kelly to slot home.
Again though Windmill kept plugging away with Joe McLaughlin forcing Gallagher into a save just before the hour mark.
Coleraine made a raft of substitutions as we moved into the final quarter and one of them, Aaron Jarvis, smashed home a fifth with 13 minutes to go.
And right at the death fellow sub McLaughlin lashed home from outside the area.
Coleraine: Gallagher,Kane, Mullan, Brown, Lowry (McLaughlin 65), Carson (Jarvis 65), O'Donnell, Glackin, Allen (Parkhill 73), Kelly, Shevlin (McKendry 66).
Subs: Henderson, Bradley, Traynor.
Windmill Stars: O'Hagan, McAteer, Larkin (Magill 69), R Cunningham, Devlin, Maguire, McLaughlin P Cunningham 78), McCabe (T Grant 61), White (Quinn 77), McGrath, Fitzpatrick (J Grant, 60).
Subs: McKenna, McKeown.
Referee: Christopher Morrison