McCoist's side swerved the Scottish Premiership champions and were paired with St Johnstone in the last eight of the competition.
It has been two-and-a half-years since the last Old Firm meeting following Rangers' demotion into the lower leagues, and the 52-year-old says that he was not "pining" for a reunion.
"St Johnstone are a really solid, hard-working team which ended up winning the Scottish Cup quite comfortably last season," he told Sky Sports News.
"As much as we're pleased with the draw, we've certainly not underestimating the task ahead of us.
"We certainly weren't pining for an Old Firm game and we would take whoever the cup draw gave us. It's going to be a tough game against St Johnstone. It's one which can hopefully be put on the back burner a little bit."
Celtic face a quarter-final clash with Partick Thistle.