Yes, three halves. Or, I suppose, three thirds. The first half hour, the middle half hour (fifteen minutes either side of half-time) and the final half hour.
Blues actually made some changes to their side for the first time in what seems like years. Stuart Parnaby, Gregory Vignal, Keith Fahey, Lee Carsley, Damien Johnson and Kevin Phillips all came in, whilst Stephen Carr, Scott Dann, James McFadden, Seb Larsson, Lee Bowyer and Christian Benitez all either had the weekend off or sat on the bench.
The first third was fairly even with neither team particularly settling. Forest kept the ball well but didn't look particularly threatening, whilst Blues were a little more direct, but again, didn't create much.
With other players coming in, Blues really lost some of their impetus, particularly in the midfield. With the changes, it was a little bit of a flashback to when Blues weren't as good. Carsley suddenly reminded everyone of his limitations. When he collects the ball from his defenders, unlike Bowyer and Barry Ferguson, he lacks the ability to turn on the ball and move forward. He therefore turned no more than 90 degrees either way, playing the ball back to another defender, rather than prompting any kind of forward movement.
Blues weren't helped by a couple of first half injuries. Parnaby - whose recent injuries will have been a set back to his World Cup hopes - was forced off, with Gary McSheffrey coming on. That meant that Fahey moved from the left to the right with Damien Johnson going to right back.
Carsley himself was then injured, perhaps straining muscles when having to turn and face the opposition goal. He was replaced by Lee Bowyer who was probably annoyed at having to take his tracksuit off in the freezing conditions.
These changes did disrupt Blues, but in fairness to Forest, they upped their game too, moving into the second third of the game. Suddenly their neat possession football became a little more threatening, helped by some excellent movement from Robert Earnshaw and Dexter Blackstock up front and the likes of Chris Cohen, Paul Anderson and some guy with a Polish sounding name (who had a cracking game) behind them. Forest began to drag Blues all over the place and caused them some problems. Blues were suddenly hanging on, with Forest hitting the bar from one corner.
This continued at the start of the second half, and Blues weren't helped by some shocking performances, notably from Vignal and Fahey. Vignal was caught out on a number of occasions and then kept failing to deliver when well place going forward, whilst Fahey - normally so assured in possession - continually misplaced passes. Cameron Jerome also struggled. Or couldn't be bothered.
Joe Hart was forced into one fine save as Forest continued to bombard Blues. Towards the end of the second third, it looked like the home side would finally get their reward when Vignal's miserable afternoon got worse as he gave a penalty away.
Earnshaw stepped forward, staggered his run up cleverly so that Hart committed himself and dived to his left. With Hart now gone and almost lying on the floor, all Earnshaw had to do was roll the ball the other way. However, he spotted someone he didn't like in the upper tier of the Trent End and tried to hit them instead. The clown.
Moments later Hart was forced into another fine save to deny Earnshaw, but suddenly as we moved into the final third of the match, Blues began to take control. Earnshaw's penalty miss seemed to knock the wind out of Forest and ignite Blues.
Within minutes it had switched from Blues being unable to get out of their half to Forest being unable to get out of theirs. Phillips hit the post with a fine strike, then missed a one-on-one that you'd have put your house on him scoring (before McSheffrey cocked up the rebound) and then Phillips was wasteful when he had good options.
Roger Johnson also headed across the face of the goal from a clever free-kick as Blues bombed forward. McSheffrey had switched with Fahey and gone wide right, and in fairness to him, he looked as effective as he has done for quite some time and deserves some credit for his performance.
However, Blues couldn't make the breakthrough and a game between two unbeaten sides that people had said "something has to give" actually showed that, nothing was going to give - both are still on long unbeaten runs.
If either side deserved to win, it was probably (just) Forest, but a draw may have been the fairest result with the way the game went. In truth, it was always a tricky looking away game for Blues given Forest's form and then the subsequent changes that Blues made to their side. When you add in the injuries picked up during the match and the penalty miss, Blues can be thankful that they're still in the competition and will fancy finishing the job in the replay now. However, Forest haven't lost away from home all season, so it won't be easy.
It was a decent run out for some of Blues' fringe players - McSheffrey and Damien Johnson both impressed, especially as Johnson was immediately back to his normal selfless role of, ten minutes into his first game back and playing in his natural position, being shoved into defence to help out and performing admirably.
However, you do have to say that some of the other performances (Vignal, Fahey, Carsley, possibly even Phillips) illustrated the thinness (or lack of quality) of Blues' squad and the fragility should there be a few injuries to the "usual" starting eleven. Hopefully that can be resolved a little over January, however.
All in all, a fairly forgettable game but a result that Blues had to scrap to get. They did get it (as with a few results lately, you have to think that the "old" Blues would have got beat) and can look forward to a home replay against a lower league club - one they should win to progress.
On a final note, it was nice to hear the Forest fans singing at the 4,500 travelling fans, "where were you when you were shit?" It was further confirmation that, for the first time in a long time, Blues aren't shit. Which is nice.