CRISTIANO RONALDO will undergo revolutionary stem cell therapy in a bid to be fit to face Manchester City.

The Real Madrid star missed yesterday’s goalless draw in the first leg of their Champions League semi-final with a hamstring injury.

He had been expected to play after being rested for the weekend win over Rayo Vallecano but aggravated the problem in training on Monday.

Cristiano Ronaldo was ruled out of goalless first leg at the Etihad with hamstring tear

Ronaldo, 31, initially felt the issue in the final minutes of last week’s victory against Villarreal, however Madrid declared it was simply cramp.

A scan in Manchester revealed a slight tear — although Ronaldo reportedly claimed he would have played had it been a final.

The Portuguese ace has now returned to the Spanish capital and will receive a round treatment to repair the damage.

Ronaldo was set to play in first leg but aggravated hamstring injury in training

Real Madrid could not find a way past Joe Hart in Etihad stalemate
Real Madrid boss Zinedine Zidane will decide whether to risk Ronaldo for return leg at the Bernabeu on Wednesday

He will definitely miss title-chasing Real’s crucial La Liga clash Real Sociedad on Saturday.

And he faces a nervous wait to see if he can line up in the return leg against City next week.

It is understood Madrid medics fear Ronaldo may only be able to take a place on the bench in the Bernabeu showdown — which would hand a major boost to Manuel Pellegrini’s side.

Ronaldo has scored sixteen goals in ten Champions League games this season

Medical staff will assess the player’s fitness next Wednesday ahead of the tie — and boss Zinedine Zidane will make a decision at the last minute whether to include him.

The treatment is similar to that received by tennis ace Rafael Nadal on his recurring knee injury.

A sample of healthy cells from the star’s blood or bone marrow is injected into the problem area to help speed up recovery.

Rafael Nadal underwent similar stem cell treatment on his injured knee

Ronaldo has scored sixteen goals in his ten Champions League games so far this season.

The winner of the tie will earn a place in the final in Milan on May 28 against either Real’s city rivals Atletico Madrid or tournament favourites Bayern Munich.