Galvin strikes for Blues but youngsters stunned
Chris Speed gave the travelling side an early lead, as some good link-up play put him through on goal, where he applied a cool finish.
The scores were levelled shortly after half-time, with Cory Galvin rounding off a fine first-half performance with a good finish.
Despite Town dominating most of the play, Crewe took the lead for a second time through Dominic Smith, with the striker scoring from inside the box.
Four minutes later and Blues were stunned as Crewe scored again, Smith turned provider for Speed who tapped home from close-range for his second of the game.
Speed got his hat-trick late on, combining with Smith again to make the room for a shot that went in off the left post.
Crewe started brightly and were awarded for their efforts in the fifth minute. O'Neil flicked the ball on with his head into the path of Speed, who broke into the box and touched the ball passed the on rushing Michael Crowe.
The young Blues grew into the game after conceding and could have been level in the 12th minute, but Cemal Ramadan's shot from the edge of the box was saved by Crewe 'keeper Robbie Johnson.
Town continued to create chances and their best opportunity of the first-half came from a great pass from captain Joe Robinson. The centre-back played a great ball over the top to Ramadan who took a touch to see him one on one with Johnson, but his shot went straight to the Crewe stopper.
Seven minutes after the restart and Town got the equaliser they deserved. Galvin picked the ball up in the box and went past one player before shooting across the 'keeper into the bottom right corner.
Johnson in the Crewe goal had been keeping his team in it and continued to frustrate the Ipswich attack, when he produced a great save from a great Gnahore shot from the edge of the box that looked destined for the top left corner.
With ten minutes remaining Crewe finished the game off as Smith gave the ball to Speed just inside the box, with the winger placing his shot in the bottom left corner, with the ball going in off the post.
Town: Crowe, Emmanuel, Walton-Owen, Willbye, Fowler, Robinson, Galvin, Smith (Dozzell 73), Clarke (Ford 63), Ramadan (Jones 67), Gnahore