Transitioning From Indoor to Outdoor Cardio

[90x]

This past week my treadmill finally gave out after numerous months of HIIT. I was doing HIIT about 3x a week with 10 sprinting intervals at 11 mph for 1 minute each followed by a rest period at 5.5 for a minute also. I decided to transition to doing HIIT outside and tried my best to replicate what I did on the treadmill. My first HIIT session outside was a humbling experience. I was only able to sprint for about 30 seconds and was barely able to complete 10 sets. Today i decided to try it again and died after like 2 reps probably because of the heavy leg workout I did two days before.Instead I did some steady state jogging for 25 minutes and was barely able to even do that. Im sure the leg workout had an effect on my results, but its completely frustrating to not be able to keep up the intensity I had indoors.

What can I do to improve my outdoor performance?

Cliffs:

Did HIIT Indoors
Treadmill broke
Did HIIT outdoors and almost died
Nearly died doing steady state outdoors
How can I improve my cardio?