It was a scoreline at full-time that flattered Gretna, as Inverness missed a host of chances in both halves, before just about holding on following a late home strike.
Gretna keeper Greg Fleming would certainly have impressed any watching scouts with a terrific display which kept his side in the game for a long period.
Inverness began the game quickly and Fleming produced three great saves inside the first five minutes, to deny firstly Dennis Wyness inside the opening minute, before pushing away a Phil McGuire header three minutes later, and then within seconds he produced another fine stop to again deny Wyness from close range.
Wyness looked ready to pull the trigger in the 15th minute, but just as he set himself to score, Craig Barr slid in with a brilliant tackle to deny the striker.
Markus Paatelainen came extremely close in the 34th minute for Inverness, when he turned inside the full-back and curled a right-foot shot past Fleming only to see the ball hit the base of the post and fly straight back into the keeper's arms.
There was controversy just before half-time, when referee Mike Tumilty pointed to the penalty spot after a handball from Gretna's Abdul Osman, but after consulting the assistant referee he changed his decision to a free-kick just outside the box, which Don Cowie blasted over.
Just into the second half John Paul Kissock saw his terrific 25-yard shot rattle the bar and Inverness keeper Michael Fraser eventually gained control of the loose ball.
Ten minutes into the second half Inverness were again looking for a penalty after Dougie Imrie appeared to be fouled in the area by Fleming, but the referee decided instead to book Imrie for diving and award a goal-kick.
Imrie almost headed his side in front in 58 minutes, after good set-up play had created the chance but he headed just over.
Eventually the visitors grabbed the lead, Imrie was the provider with a pinpoint pass through the Gretna back line, straight into the path of Roy McBain, and he made no mistake by hammering a left-foot shot past Fleming after 71 minutes.
Two minutes later the lead was doubled, Cowie managed to slot the ball home at the second attempt, after Fleming had only just stopped his initial shot, but Cowie reacted quickly for an easy finish.
Gretna grabbed the consolation ten minutes from time, after Kyle Naughton had produced a great shot that Fraser could only push out, straight into the path of Craig Barr and he made no mistake with a left-foot shot.