Ferguson made 10 changes and gave in-form Berbatov the night off as he tried to assess the standing of some new players in the Champions League opener at Old Trafford.
But as United struggled to overcome Rangers' blanket defence, Ferguson found himself lacking someone with the guile to find a way through once Antonio Valencia had departed with his horrific injury.
"We wanted to see how Javier Hernandez would do in a full game," said Ferguson.
"Because of that we left Berbatov out and his form has been absolutely fantastic.
"He has been one of our best players this season and his ability to create in tight situations would have made a difference."
Yet Ferguson insisted he had no alternative as, entering such a congested phase of the season, he needed to know what options he has at his disposal.
"We wanted to find out about one or two players," he said.
"But seven or eight of them played against Chelsea in the Community Shield, so we weren't short of players we needed to win the game.
"There were plenty of good players on the pitch."
Unfortunately for United, they kept running into a brick wall, as the five Rangers defenders were protected by four midfielders right in front of them.
Only Darron Gibson came close to breaking the deadlock with a couple of fierce long-range efforts that whistled past the post.
Wayne Rooney had one half-chance on his return to action but nothing clear cut and a measure of how awkward United found their opponents was shown by the fact they were forced to wait until the 84th minute to force their first corner.
"It was a frustrating night for us," he said.
"Rangers' system of play was very difficult to break down.
"I don't know if playing anyone else would have made any difference.
"They were well organised and defended so deep, it was difficult to open them up at all.
"We didn't test their goalkeeper at all, apart from a couple of shots straight at him.
"It was a really difficult night."