I want to Filter all content after match with the content and bring the first value after the "."

I have an output something like this:

Output:

```
product: 13.6.0.35_0

```

More specifically, I need only the first two digits and the first digit after the dot, remembering that we should not cling to the values in the issue, but rather on the method of filtering the content.

Expected:

```
13.6

```

I tried something like:

```
echo "product: 13.6.0.35_0" | grep -ow '\w*13\w*'

```