Enumerable.Last<T>() and C# arrays

Say I have a simple array:

double[] myDoubleArray = new double[] { 0, 1, 2, 3, 4, 5 };

Is this as performant:

double last = myDoubleArray.Last();

as this?

double last = myDoubleArray[myDoubleArray.Length - 1];

Will Last() enumerate over the entire array even when it can make the above optimization?

If I passed some other IEnumerable (say one that was yielded), Last() would have to enumerate the sequence. I prefer using Last(), because code looks cleaner, but I would not make a sacrifice if it enumerates the sequence.