They were a nightmare to play against and then who did they have playing off them? Henrik Larsson, who could drop off or spin in behind and create all sorts of havoc.
With the possible exception of Jan Vennegoor of Hesselink, I don't think they have had anyone in the Sutton or Hartson mould since. If they could add someone with a wee bit of that kind of presence and a wee bit of pace it would make an incredible difference to the team.
While Georgios Samaras had the height and the pace, he didn't have the presence. He ended up going wide left naturally, so Celtic started playing him there. But what they needed most and still need is an out- and-out striker who loves the battle with the centre-halves. Perhaps they thought Amido Balde was going to be that type of player, but at a club such as Celtic they need someone who is proven in the role, not a young guy who doesn't have the experience.
I don't know too much about Stefan Scepovic, the Sporting Gijon striker Celtic have been linked with, but if they get him, let's hope he has the attributes to add that missing dimension.
One player I think wouldn't be a bad shout, even though he isn't the tallest, is Nadir Ciftci at Dundee United. He loves it when you get the ball up to him, has a good touch, excellent game intelligence, a physical presence and can run. He is untried at Champions League level but I think he has the quality to play there.
Celtic can wait until after Tuesday's play-off second leg against Maribor before making any transfer moves, but if they have to throw three or four million at the right player then they should do it.
As for whether Celtic will make the group stage, I wouldn't rule anything out but for me Maribor haven't progressed since they put Rangers out a few seasons back. I couldn't believe how badly Rangers played that night and Celtic would have to do the same to miss out after getting the draw in Slovenia.
While I am confident Celtic will qualify, if they have any realistic ambitions of being competitive in the group then Virgil van Dijk must stay. Efe Ambrose continues to make mistakes, while Jason Denayer looks great but is young and inexperienced.
Even Van Dijk sometimes gets caught out at that level, but I love him as a player. I think he is good enough to play at the top level in England but if Celtic make the group stage there can't be any more players going out of the door. It is a case of keep what you have and add to it.
I would be looking at bringing another left-back in because while Emilio Izaguirre can create things going forward I don't think he can defend. You might get away with that domestically but not in the Champions League.
With James Forrest injured I can understand why Ronny Deila has brought Mubarak Wakaso in on loan from Rubin Kazan, but the priorities for me are a left-back and a tall physical striker.
The last week of the transfer window used to be a busy one for Scottish clubs but it will be deadly quiet this year. Aberdeen have spent their quota, and most clubs don't money to throw around.
For me, Rangers could still do with another and someone who can boss central dominant central midfielder who can boss it in there. But times are tight at Ibrox and I would be surprised if Ally McCoist sees any more cash.
AS an Ayrshireman, I can't wait for the Kilmarnock-Ayr United League Cup tie on Tuesday night. I might not have played for either club, but I've been to those games and I've seen what they mean.
Killie look decent this year, having added the strength and firepower of Josh Magennis, Tope Obadeyi, Lee Miller and Michael Ngoo, and Ayr might have had a better chance if they were at home.
But they have a good record in this fixture, it will still be a great game that will pull in a big crowd, and in a derby anything can happen.