A late collapse stunned the Melton Foxes after they missed a golden chance to forge a big first-half lead.
A superb first half performance could easily have seen Melton head into the break three goals up, and Shaun Smith put them in front shortly after the restart.
But the team then turned in possibly their worst 25 minutes of defending so far this season as the visitors notched five goals.
A big and strong Blaby side had the first chance after five minutes via a miscued clearance, but keeper Chris Lovegrove produced a good save.
A minute later Cameron Ainge put Shaun Smith through, but the normally lethal striker sliced his final effort wide.
The Blaby number nine then scooped an effort over the bar after Jake Dawkins missed his clearance.
Foxes hit back and a quickly taken corner by Lomas and Rowlands ended with the latter smacking a cross-shot against the bar.
Skipper Alex Walker weaved his way into the Blaby area, but his final shot lacked pace and Rowlands broke clear and crossed low for Smith who was unable to get a touch.
Smith’s shot forced another save before Dawkin’s superb long ball sent Rowlands away, but he fired against the keeper when looking a certain scorer.
Straight after half-time Foxes went on the attack and were rewarded with a goal in the 50th minute.
Walker was brought down on the edge of the area and Smith curled a superb left-foot shot past the keeper.
But within two minutes Blaby were level when a long throw-in caused confusion in the Foxes area and keeper Lovegrove appeared to misjudge the flick-on which bounced into the corner of the net.
Blaby repeated the trick on the hour when another long throw was flicked on past a static home defence and tapped in from close range.
Foxes should have equalised seconds later when Dawkins put Rowlands through with a superb pass, but the striker shot across the face of the goal.
Blaby made them pay dearly when a long ball sent their number 10 race clear and steer a shot past Lovegrove who was slow off his line.
The visitors made it 4-0 after 70 minutes when their winger cut along the byline and crossed low for a simple tap-in.
Melton’s problems were compounded when skipper Alex Walker was sent off for a second bookable offence.
And Blaby rubbed salt in the wounds when another long ball from the left caught the Foxes napping and another tap-in made it five.
Foxes again turned in a really good performance, but as at Birstall they failed to take their first-half chances and then could not cope with an aerial bombardment from corners and long throws.
There was a special mention for 16-year-old defender Jake Dawkins who came straight to the match from East Midlands Airport following a holiday abroad.
Foxes: C. Lovegrove, A. Doherty, R. Gavin, J. Dawkins, F. Lewis, C. Ainge, A. Walker, A. Lomas, B. Carroll, S. Smith, M. Rowlands, A. Kotarba, C. Steans, A. Horobin.
* On Sunday, Foxes host Coalville Ravens at the All England Ground in the County Cup (kick-off 2pm).