The decision to start with only Billy Sharp as a recognised frontman was magnified by a 2-1 defeat for the Reds but manager O'Driscoll said his plans were subject to a late change.
"We toyed with the idea of matching up against them and going with a back three," he told the Evening Post.
"But Daniel Ayala fell ill on Friday. We told him to keep away from the ground, because he had a bug and these things have a habit of spreading.
"That gave us a problem and we had to go with a central striker and two wide people. Asides from the result, I am pleased with what we have seen."
Source: Forest MAD