The Gills' five-game unbeaten run came to an end as a last-minute goal from Max Clayton saw Crewe win a thrilling clash at MEMS Priestfield.
It was another entertaining clash involving the Gills, and their third 4-3 defeat of the campaign was another rollercoaster clash which saw the Gills fightback from 3-1 down, only to have Danny Spiller sent off before the last-gasp winner from the visitors.
Nick Powell' stunnig strike gave the Alex a half-time lead, which was cancelled out by Jack Payne early in the second half.
But the Alex - through Ajay Leitch-Smith and a second for Powell - went two goals ahead, only for Chris Whelpdale and Ashley Miller to drag the Gills back level.
There were three changes to the side that had started Tuesday's victory over Barnet with Simon King, Payne and Dennis Oli coming in for Garry Richards, Jordan Obita and Danny Kedwell.
It was a quiet opening 10 minutes or so, Whelpdale needing treatment following a clash of heads and referee Keith Stroud speaking to Olly Lee and Harry Davis following a mini-skirmish being the only noteworthy moments.
The first real opening came in the 12th minute when Whelpdale put a header wide following a long throw from Charlie Lee from the right.
In the 16th minute Lee picked up a costly booking for a nudge on Byron Moore. It was his 15th of the season which will rule him out for three games.
From the resulting free-kick, Moore was closed down brilliantly by both Charlie Lee and Payne as he shaped to shoot from the edge of the area.
At the other end Jackman had an effort blocked following a free-kick routine and then King's goalbound effort was cleared following a Lee corner.
But in the 27th minute Crewe took the lead out of the blue with an absolutely superb strike.
England Youth international Nick Powell smacked an angled 25-yard effort high into the top right-hand corner of Paulo Gazzaniga's net, the young Argentine having no chance.
The visitors, who were now in the ascendancy, went close again shortly afterwards, when Moore fired across the face of goal just inches away from onrushing team-mates.
Then Matt Tootle overlapped down the right but his dangerous low cross was thankfully clutched by Gazzaniga.
At the break Kedwell was introduced for Olly Lee and the substitution paid off almost instantly when his low drilled cross was swept home by Payne from close range just three minutes in.
Unfortunately parity lasted just three minutes. Powell went clear down the right and his low ball across the face of goal and saw Leitch-Smith somehow find the back of the net despite Gazzaniga's valiant attempt to claw the ball clear.
Things got worse a minute later when Alex added a third when another ball into the area was despatched into the far corner with some aplomb by teen sensation Powell once more as he left Gazzaniga rooted.
The 170 travelling supporters were certainly enjoying their afternoon and things could have got better but the Gills keeper beat out a Luke Murphy free-kick, shortly afterwards the same player fired a shot straight at Gazzaniga.
The Gills tried to respond and Steve Phillips in the Crewe goal somehow kept out a low left-footed drive from Whelpdale with his feet.
In the 67th minute the perspective of the game changed again as Whelpdale pulled one back, a long throw from Lee was only half cleared and the winger volleyed home with his left foot.
Two minutes later Lee, who had been walking a tightrope since his earlier booking, was replaced by Spiller, then Lewis Montrose then picked up a harsh yellow card (his 10th) which will also see him suspended.
The game was turned on its head in the 73rd minute as the Gills levelled matters as Phillips failed to hold a Kedwell header and Miller was on hand to thump home the loose ball, his first senior goal.
Referee Stroud suddenly became the centre of attention, Davis and Payne picked up yellow cards before Spiller, who'd only been on the pitch 10 minutes, was given a straight red for a lunge on Brown.
Powell had a great chance to put Crewe ahead once more, and claim a hat-trick, but saw Gazzaniga beat out his effort from six yards out then Clayton failed to get any power on a close range header.
Then in the final minute of stoppage time it was Clayton that somehow found the time and space to nod home Moore's cross, a heartbreaker the Gills didn't really deserve at that point.
The result sees the Gills remain in eighth place, a point behind Oxford United.
Gills: Gazzaniga, C.Lee (Spiller 69), King, Whelpdale, Payne, Oli (Evans 78), Jackman, Montrose, Essam, A.Miller, O.Lee (Kedwell H/T)
Unused subs: Davies, Hawkes
Crewe: Phillips, Tootle, Davis, Westwood, Artell, Dugdale, Murphy, Leitch-Smith (Clayton 77), Moore, Shelley (Brown 75), Powell
Subs: Martin, S.Miller, Pearson
Attendance: 5,428 (170 Crewe)
Referee: Keith Stroud
Assistants: Ian Crouch & John Magill
Fourth Official: Wade Norcott