Former Real Madrid attacker Predrag Mijatovic says the club have no choice but to sign another star player as he believes Gareth Bale and Karim Benzema lack the quality to fill the role.
Madrid have slumped to four defeats and a draw in their last five matches in all competitions, leaving new coach Julen Lopetegui facing a difficult fight to keep his job.
The Champions League holders have scored just once in that run, as Bale has not found the net since August, while Benzema is on a similarly poor run.
The Spanish giants have been linked with several options to replace the Portuguese star, who ended his nine-year spell in the capital to join Juventus, and Mijatovic believes they must bring someone in to fix the problem.
"When you lose a player like that, and you have to remember that you wanted to leave, you have to find another," he told Cadena Ser.
"I'm not convinced that Bale and Benzema can fill the gap of Cristiano. Comparing them with him, they are not able to give the same as him in recent years."
Failure to beat Viktoria Plzen in the Champions League this week or a bad result against rivals Barcelona in La Liga on Sunday could see Lopetegui dismissed just a few months after taking charge at the Santiago Bernabeu.
However, Mijatovic says they would be wrong to give up on the former Spain boss at this point, insisting the league can still be won despite the four-point gap with leaders Barca.
"Without any doubt it would be a mistake to throw him out, it's a bad decision," he said. "The league is very even, you have to keep the coach.
"Madrid can hardly lose against Viktoria, the Champions League is a competition made for them, if they lose they will have to make a decision, but even if they lose, we have to give Julen time.
"We do not have to look for the guilty, we have to find the solution, the players have to take this forward, Madrid will come out of this situation, I am convinced."