Preheat oven to 350°F. Grate 1 tablespoon plus 1 teaspoon peel and squeeze juice from oranges. Reserve 1 teaspoon orange peel for beets; set aside. Combine 1 tablespoon orange peel, 2 cloves garlic and pepper; press evenly onto all surfaces of beef roast.
Place roast, fat-side up, on rack in shallow roasting pan. Insert ovenproof meat thermometer so tip is centered in thickest part of beef. Do not add water or cover. Set aside.
Combine beets, orange juice and remaining 3 cloves garlic in 13×9-inch glass baking dish. Cover with aluminum foil. Roast beef in 350°F oven 55 to 65 minutes for medium rare; 65 to 75 minutes for medium doneness. Roast beets, covered, 50 minutes. Remove foil; continue roasting, uncovered, 8 to 10 minutes or until beets are tender and liquid has thickened slightly.
Remove roast when meat thermometer registers 135°F for medium rare; 150°F for medium. Transfer roast to carving board; tent loosely with aluminum foil. Let stand 10 to 15 minutes. (Temperature will continue to rise about 10°F to reach 145°F for medium rare; 160°F for medium.)
Toss beets with balsamic vinegar; sprinkle with reserved 1 teaspoon orange peel. Carve roast across the grain into slices; season beef and beets with salt and pepper, as desired. Serve beef with beets.
Nutrition information per serving: 280 Calories; 108 kcal Calories from fat; 12 g Total Fat; 4.5 g Saturated Fat; 0.5 g Trans Fat; 0.5 g Polyunsaturated Fat; 6.1 g Monounsaturated Fat; 70 mg Cholesterol; 170 mg Sodium; 18 g Total Carbohydrate; 4 g Dietary Fiber; 25 g Protein; 4 mg Iron; 759 mg Potassium; 8.3 mg Niacin; 0.4 mg Vitamin B6; 2.4 mcg Vitamin B12; 9.1 mg Zinc; 30.8 mcg Selenium; 7.2 mg Choline;