Combine stew meat, garlic, red wine, marsala, & olive oil in a gallon ziploc bag. Close bag. Shake or squish around. Refrigerate for 2 hours to overnight.
Place beef mixture, mushrooms, & tomatoes in Dutch oven or large pot. Add beef broth. Stir together. Bring to a boil over high heat. Cover. Reduce heat to low. Simmer for 1 hr.
Add potatoes, carrots, & celery. Cover. Simmer for 30 minutes.
Remove beef & vegetables from pot with slotted spoon into a large bowl. Cover & set aside.
Stir water & cornstarch in small bowl until smooth. Pour cornstarch mixture into pot. Increase heat to medium. Cook & stir until sauce is slightly thickened.
Return beef & vegetables to sauce. Cover. Reduce heat to low. Simmer for 30 minutes. Serve.