Concerned Scott McDonald has warned Celtic they can't repeat the recruitment mistakes of last summer - like Ivan Toney.
The former Peterborough star a target for the dethroned Premiership champions but eventually joined Brentford last summer.
Toney, who has scored 29 goal for the Championship side in his debut season, has proved to be a costly miss for the Hoops.
Instead, Celtic spent £5million on Albian Ajeti, who has played little more than a cameo role.
With Odsonne Edouard struggling to hit the heights of last season, the likes of Leigh Griffiths, Ajeti and Partyk Kilmala have failed to pick up the slack.
Australian hitman McDonald insists Celtic must find a "real number nine" amid the struggles of their attackers this term - especially Swiss flop Ajeti.
He insists all the signings this summer must be spot on if the title is to be brought back to Glasgow's east end as he panned the recruitment drive last summer.
McDonald told the Sunday Post : “Lessons need to be learned from last summer.
“Celtic had two excellent goalkeepers in Fraser Forster and Craig Gordon. For various reasons, both didn’t sign on again.
“The club also searched for a striker, and Toney appeared to be their No. 1 target.
“I remember watching him two or three years ago for Peterborough against Middlesbrough, and he really caught my eye.
“He had presence and pace. He looked to have the raw materials to go a long way.
“When Celtic were linked with him, I was excited. There was no doubt in my mind he’d do well. But a fee couldn’t be agreed and he went to Brentford. That was a blow.
“Look at how well he is doing in the English Championship, so it’s a sore one to miss out on.
“The club ended up getting Ajeti, but it’s not been a great season for the Swiss striker. He has been in and out.
“So we know how hard it is to find a proper No. 9. It will not be easy to find one.
“Indeed, Celtic might be looking for two strikers in the summer window if Leigh Griffiths and Odsonne Edouard follow Patryk Klimala, another disappointment this season, out the door. It makes it all the harder.
“Leigh scored a good goal against Aberdeen in midweek, and that will have done his case no harm.
“But he has just eight goals in 26 appearances this season, and Celtic must find someone who will get them at least 20 goals a season.
“A Celtic striker is judged on numbers, the amount of times he puts the ball in the net. He’s not judged on performances.
