Rangers cruised to a 2-0 win at Celtic on Saturday to send out a statement of intent in the title race, winning via a Connor Goldson double.
Both Celtic and Rangers used the recent transfer window to strengthen their respective squads in anticipation of a crunch Scottish Premiership title battle and European campaigns.
Dalziel thinks that Rangers have operated more shrewdly in the transfer market of late, with Celtic making signings which have not turned out to be positive.
The former top flight striker admits that even with centre-back Duffy, who Celtic signed on loan, he expected to see more and questioned whether the Irishman is a leader of men.
Dalziel said on Radio Clyde: “I do think in the transfer market they have been better than Celtic.
“I know it’s very easy to pick holes in different things, but the first time I saw the goalkeeper it wasn’t for me, [Patryk] Klimala, I feel so sorry for the lad, [Ismaila] Soro, how much did they pay for him and he’s not even been seen.
“Even Duffy. I was expecting so much off Duffy when he came up.
“Now, I know he started with a couple of headers, but I was looking for a real leader, a man that would put people into positions and be strong. I don’t see that in him.
“So a lot of the transfer market for Celtic has not been positive.”
The derby defeat means that Celtic are now four points behind Rangers in the Scottish Premiership standings, though they do boast a game in hand on their rivals.
Both Rangers and Celtic are in Europa League action this week, against Standard Liege and AC Milan, respectively.