How to expand a MudBlazor table with only 1 row?

When I show the MudBlazor table, it initially looks like this:

In the code, I'm preloading an empty row, so when I click in the bottom area below the line under "Outcome", it expands and looks like this:

How do I programmatically get the table into the state of the second image - showing the blank row?

I've tried using SetSelectedItem with a StateHasChanged(), but that didn't seem to expand that row. Does anyone have any ideas?