Celtic midfielder Kris Commons believes the Scottish champions` failure to sign a top-class striker to replace Gary Hooper was the key to their Champions League exit.
The Scottish champions` miserable European campaign ended on a dispiriting note as Barcelona cruised to a 6-1 win at the Camp Nou on Wednesday.
That left Celtic bottom of Group H with three points and just three goals in their six matches.
Commons is convinced the main reason for Celtic`s flop this term was the loss of last year`s top scorer Hooper, who moved to Norwich in pre-season.
Celtic manager Neil Lennon tried to replace Hooper with cut-price deals for Teemu Pukki and Amido Balde, but it is Commons who is the most prolific this season with 12 goals.
Commons says the Parkhead club needed to splash out up to £10 million ($16.3 million, 11.9 million euros) to replace Hooper and he told BBC Sport: "In a Celtic team you are looking for a striker to get you 20-30 goals. At the minute, we haven`t quite got that.
"I know people are working hard on and off the field to try and get us the goals but replacing someone like Gary Hooper is going to cost you between £6 million and £10 million and at the minute we are not willing to spend that.
"Looking back at the first AC Milan game, we played really well over there and came away with nothing.
"That`s kind of been the story of this campaign. We`ve not had a great deal of lady luck, we`ve not really performed to the levels we know we are capable of.
"We`ve been playing well in the league but not shown it in the Champions League. This is cut throat level football.
"We need to rebuild for next year because the target is to qualify for this competition again.
"We`ve got a lot of good characters and the manager wants to strengthen again with players that can take us to the next level because we have lost some big players."