The veteran goalkeeper was in danger of being the main talking point from a cup tie that was more laboured than explosive when he gifted Queen's Park a goal to level the match with a quite disastrous blunder. He made the cardinal sin of coming for a ball that was never his and Tony Quinn, a plumber by trade, happily headed the ball into the net to give Simonsen that sinking feeling.
Boyd, however, proved his predatory worth to spare the goalkeeper's blushes with two headers, opening the scoring in seven minutes and then scoring what proved to be the winner.
"There were a few positives but there were some negatives too and we will need to address them," said Ally McCoist, the Rangers manager. "We can't afford to make the same mistake against Inverness who are the in-form team in the country.
"I will have to see their goal again but my initial reaction was that he should have stayed on his line. It was sore one for him and for us."
In the end Rangers were comfortable enough and might have scored more goals in the second half but they will need to play much better than this if they are to trouble the side who currently lead the top flight.
When the visitors took the lead inside seven minutes it seemed that it would be a straightforward evening. It was an excellent goal too and McCoist must have been thinking that safe passage would be assured. Nicky Law worked to find space on the right side of the Queen's defence and delivered a great cross which Boyd powered into the net.
Two minutes earlier Lee McCulloch had forced a terrific save from Willie Muir when he connected with Nicky Clark's cut back from the left.
Then in nine minutes Lewis Macleod thought he had scored a second goal when he headed Arnold Peralta's cross past Muir but he was given offside. It was careless from the young midfielder who should have been able to time his run better and it was an important moment because a second goal at this juncture would have deflated the SPFL League 2 side. As it transpired, Rangers' tempo dwindled and Queen's looked more organised at the back, galvanised from the decision going their way.
McCulloch completely miss-hit a shot from the edge of the box in 16 minutes after Peralta had knocked down Mohsni's long pass.
Then Boyd tried to beat Muir with a toe-poke after Macleod's speculative effort had spun into his path but the Queen's goalkeeper was equal to it.
Rangers had become predictable in their build-up although Queen's scarcely threatened. That all changed in the 31st minute. McCulloch gave away a free kick for a foul on Vincent Berry just inside Rangers' half and Darren Millar clipped the dead ball towards the edge of the penalty area.
Simonsen made the disastrous error in judgment of running from his line in an attempt to win the ball and Quinn got above everyone to flick a header into the unprotected Rangers net. It was a calamitous error and Queen's could hardly believe their luck scoring with their first attempt at goal.
Simonsen has a previous conviction, having gifted a goal to Dundee United in last season's Scottish Cup semi-final and the half-time discussion with his manager could not have been pleasant. However, Rangers regained control of the game early in the second half when they grabbed their second goal.
There were 53 minutes on the clock when Clark's shot was diverted into the path of Peralta and he cleverly crossed to the back post where Boyd was unmarked and had the simplest of tasks to head the ball into the net.
Queen's, it seemed, had little to offer by way of retaliation and the only surprise was that Rangers did not add to their lead.
The tireless Clark headed just wide in 77 minutes from Peralta's cross. Then a minute later Vincent Berry cleared Mohsni's header off the line after Macleod had zipped a corner in from the left.
In the end Rangers were comfortable but they will need to reach a higher level if they are to hold hopes of further progression.