Montrose slipped closer to the basement of League Two after a comprehensive 4-0 defeat against East Stirling at Ochilview.
Shire leapfrogged the visitors in the table with some ease to leave Montrose manager George Shields bemoaning a pretty dire performance.
“They have been told that that was not acceptable,” he said. “We didn’t turn up, never got going and it’s very disappointing.
“It has to be our worst performance of the season and I did not expect it.
“We had been doing well in training during the week and last week we played well in the 22 draw with Annan so I did not expect the performance we got today.”
The Links Park outfit have a free week on Saturday and Shields added: “It will give us a bit more time to work on where we went wrong today before we play Berwick on Tuesday week.
“Today, though, was one to forget.”
Neither side were dominant until Shire broke the deadlock in the 19th minute. The Montrose defence failed to clear a David Greenhill corner and David McKenna swept the loose ball into the net from six yards.
It was a pretty soft counter and the second nine minutes later had an element of luck about it. McKenna fired in a free-kick from 25 yards that was going wide but Celtic loanee Luke Donnelly stuck out a boot and diverted the ball into the net.
A couple of Terry Masson shots that Richard Barnard dealt with were all the visitors could muster in the first period but, given they were offering little resistance, it was no surprise when the home side made it three in the 59th minute.
McKenna raced to the right byeline before firing low to the near post and Max Wright clipped past Joe McGovern from the angle of the six-yard box.
Sub Billy Vidler added a fourth in 81 minutes to complete the scoring by rounding McGovern before slotting into the empty net from 10 yards.
Stephen O’Neil forced a good save out of Barnard with a powerful drive just before that but it could not disguise the home side’s superiority and Shire assistant manager John Allison said: “That’s probably as well as we have played this season but it has been coming.”