In which movie Sylvester Stallone asked to fight for real, which resulted him going to hospital?

During Rocky-4 shooting Dolph Lundgren was given the role of the Soviet boxer - Ivan Drago. Stallone asked Lundgren to fight for real, so the scene looks as realistic as possible. After couple of punches Stallone was taken to the hospital, where he recovered for 8 days.

SOURCE: en.wikipedia.org

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