However, Clyde will consider themselves hard done by given that they had earlier hit the bar with the scores level.
The visitors got off to a flying start with a third minute goal. Allan Jenkins appeared to have been fouled but the advantage was played in favour of Ryan McGuffie, whose cross into the box was headed home by McMenamin.
Clyde keeper Peter Cherrie got a hand to the ball but the power of the header proved decisive.
Gretna looked set to overrun the home side, but the match gradually deteriorated into a stop start affair with neither side able to impose themselves on the proceedings.
Clyde subsequently equalised after 24 minutes from a corner kick. Stephen O'Donnell played the ball short to Kevin Bradley and Dougie Imrie was on hand to outjump keeper Alan Main and force the ball in at the far post.
In the second half play flowed from end to end without any clear sign of a breakthrough, until Craig Bryson powered a header off the bar with Main well beaten.
Gretna eventually celebrated the escape by scoring with two minutes left which gave Clyde little chance of recovery.
Gavin Skelton touched a corner to Derek Townsley, who picked out Martin Canning whose goalward shot was turned in by McMenamin at close range.
Clyde's Michael McGowan was red-carded for an unnecessary assault on the scorer McMenamin down by the corner flag in stoppage time.