I know that this is bit complex, but this is the way I always use to find the race I want quickly without scrolling forever!
First find the league page of the race you want to see, then click box of the next igp race. Only do this 5 minutes or less before the race otherwise you will wait for a long time.
Then you need to click on the tier(pro/rookie/elite) that want to watch and look at the link at the top of the page!
Copy and paste the 7 digit number in the link,
then type "https://igpmanager.com/race/live.php?id=XXXXXXX" replacing the Xs with your number. This will take you to the race much quicker than scrolling through the Spectate page
this will work every time!
Alternatively, if you are in the same tier as the race you want to watch, just click the live button that appears on the league page after qualifying!