Lee Hughes scored a hat-trick as Coventry went on the rampage at Crewe.
Hughes produced a deadly performance in front of goal.
Crewe seemed to have a chance at the start of the second half, after going in at half-time just one goal down at 1-2.
But Coventry poured on the style in the second half and left the Cheshire side for dead.
Hughes created the first goal. Crewe keeper Ademole Bankole could only spoon Hughes' cross into the air. Delorge beat the giant keeper to the ball to knock it in.
Crewe equalised in injury time at the end of the first half. Shaun Smith curled in a corner and Rob Hulse powered a near-post header into the back of the net.
But seconds later Coventry were back in front when Hughes turned Steve Foster before driving in a curled shot from 15 yards.
And the former West Brom man struck again after 47 minutes.
Lee Mills flicked on De Lorge's long throw-in and Hughes beat Bankole to the ball to nod home.
Missed penalty
After 58 minutes it was Delorge's turn. Crewe's David Wright deflected a cross back across goal and Delorge pounced to drive home past a stranded Bankole.
David Thompson made it five after 67 minutes.
David Wright and Bankole got into a muddle at the back, allowing the former Liverpool midfielder to nip in and score into the empty net off the post at the second attempt.
Then in the 70th minute Hughes made it 6-1 when he ran onto Thompson's through-ball before barging past Bankole and Efe Sodje to finish.
Crewe boss Dario Gradi responded to the collapse by substituting his Nigerian goalkeeper for Trinidad & Tobago international Clayton Ince.
But he could do little to stop a nightmare end to Crewe's day. They got a penalty after 87 minutes, but skipper Shaun Smith drove it against the crossbar.
Crewe had had their chances early on and should have taken the lead when David Vaughan unlocked the Coventry defence with a inch-perfect pass to Rob Hulse.
The striker rounded Marcus Hedmen but somehow Marcus Hall managed to boot it off the goal line.
Crewe: Bankole, Wright, Foster, Sodje, Smith, Lunt, Sorvel, Brammer, Vaughan, Ashton, Hulse. Subs: Ince, Walton, Jack, Rix, Little.
Coventry: Hedman, Quinn, Breen, Hall, Delorge, Konjic, Safri, Healy, Thompson, Mills, Hughes. Subs: Davenport, Pead, Betts, Fowler, McSheffrey.
Referee: G Salisbury (Preston).