using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var eventStats = new TennisStats{ Id = 1, };

        Console.WriteLine( eventStats.Score?.ToDictionary(x=>x, x=>x) ?? new Dictionary<string, string>());

    }

}

public class TennisStats

{

    public int Id {get;set;}

    public List<string> Score {get;set;}

}

​