A 64-year-old man hospitalized with COVID-19 developed a serious fungal infection from Sarocladium implicatum, an unusual fungus rarely found in humans. The infection appeared in his bloodstream and lungs while his immune system was severely weakened by the virus and medications. Doctors identified the fungus using genetic testing and successfully treated him with voriconazole antifungal medication. This case highlights how COVID-19 patients in intensive care are vulnerable to rare opportunistic infections that require specialized laboratory testing to identify and treat.